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| Registros recuperados: 27 | |
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| Slobodkina, G. B.; Kolganova, T. V.; Chernyh, N. A.; Querellou, Joel; Bonch-osmolovskaya, E. A.; Slobodkin, A. I.. |
| A thermophilic, anaerobic, chemolithoautotrophic bacterium (designated strain SL50(T)) was isolated from a hydrothermal sample collected at the Mid-Atlantic Ridge from the deepest of the known World ocean hydrothermal fields, Ashadze field (12 degrees 58' 21 '' N 44 degrees 51' 47 '' W) at a depth of 4100 m. Cells of strain SL50(T) were motile, straight to bent rods with one polar flagellum, 0.5-0.6 mu m in width and 3.0-3.5 mu m in length. The temperature range for growth was 25-75 degrees C, with an optimum at 60 degrees C. The pH range for growth was 5.0-7.5, with an optimum at pH 6.5. Growth of strain SL50(T) was observed at NaCl concentrations ranging from 1.0 to 6.0% (w/v) with an optimum at 2.5 % (w/v). The generation time under optimal growth... |
| Tipo: Text |
Palavras-chave: Thermophile; Archaeon. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6598.pdf |
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| Zeng, Xiang; Birrien, Jean-louis; Fouquet, Yves; Cherkashov, Georgy; Jebbar, Mohamed; Querellou, Joel; Oger, Philippe; Cambon-bonavita, Marie-anne; Xiao, Xiang; Prieur, Daniel. |
| A novel hydrothermal site was discovered in March 2007, on the mid-Atlantic ridge during the cruise 'Serpentine'. At a depth of 4100 m, the site 'Ashadze' is the deepest vent field known so far. Smoker samples were collected with the ROV 'Victor 6000' and processed in the laboratory for the enrichment of anaerobic heterotrophic microorganisms under high-temperature and high-hydrostatic pressure conditions. Strain CH1 was successfully isolated and assigned to the genus Pyrococcus, within the Euryarchaeota lineage within the Archaea domain. This organism grows within a temperature range of 80 to 108 degrees C and a pressure range of 20 to 120 MPa, with optima for 98 degrees C and 52 MPa respectively. Pyrococcus CH1 represents the first obligate piezophilic... |
| Tipo: Text |
Palavras-chave: Thermococcales; Extremophile; Deep sea hydrothermal vent; High hydrostatic pressure; Archaea. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6812.pdf |
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| Henneke, Ghislaine; Flament, Didier; Hubscher, Ulrich; Querellou, Joel; Raffin, Jean-paul. |
| DNA polymerases carry out DNA synthesis during DNA replication, DNA recombination and DNA repair. During the past five years, the number of DNA polymerases in both eukarya and bacteria has increased to at least 19 and multiple biological roles have been assigned to many DNA polymerases. Archaea, the third domain of life, on the other hand, have only a subset of the eukaryotic-like DNA polymerases. The diversity among the archaeal DNA polymerases poses the intriguing question of their functional tasks. Here, we focus on the two identified DNA polymerases, the family B DNA polymerase B (PabpolB) and the family D DNA polymerase D (PabpolD) from the hyperthermophilic euryarchaeota Pyrococcus abyssi. Our data can be summarized as follows: (i) both Pabpols are... |
| Tipo: Text |
Palavras-chave: DNA polymerase; Strand displacement; Gap filling; Euryarchaea; DNA replication. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-423.pdf |
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| Roussel, Erwan; Konn, Cecile; Charlou, Jean-luc; Donval, Jean-pierre; Fouquet, Yves; Querellou, Joel; Prieur, Daniel; Cambon-bonavita, Marie-anne. |
| The distribution of Archaea and methanogenic, methanotrophic and sulfate-reducing communities in three Atlantic ultramafic-hosted hydrothermal systems (Rainbow, Ashadze, Lost City) was compared using 16S rRNA gene and functional gene (mcrA, pmoA and dsrA) clone libraries. The overall archaeal community was diverse and heterogeneously distributed between the hydrothermal sites and the types of samples analyzed (seawater, hydrothermal fluid, chimney and sediment). The Lost City hydrothermal field, characterized by high alkaline warm fluids (pH>11; T<95 °C), harbored a singular archaeal diversity mostly composed of unaffiliated Methanosarcinales. The archaeal communities associated with the recently discovered Ashadze 1 site, one of the deepest active... |
| Tipo: Text |
Palavras-chave: Archaea; Hydrothermal vent; Mid-Atlantic Ridge; 16S rRNA gene; Sediment; Ultramafic. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00067/17836/15573.pdf |
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| Postec, Anne; Lesongeur, Francoise; Pignet, Patricia; Ollivier, B; Querellou, Joel; Godfroy, Anne. |
| The prokaryotic diversity of culturable thermophilic communities of deep-sea hydrothermal chimneys was analysed using a continuous enrichment culture performed in a gas-lift bioreactor, and compared to classical batch enrichment cultures in vials. Cultures were conducted at 60 degrees C and pH 6.5 using a complex medium containing carbohydrates, peptides and sulphur, and inoculated with a sample of a hydrothermal black chimney collected at the Rainbow field, Mid-Atlantic Ridge, at 2,275 m depth. To assess the relevance of both culture methods, bacterial and archaeal diversity was studied using cloning and sequencing, DGGE, and whole-cell hybridisation of 16S rRNA genes. Sequences of heterotrophic microorganisms belonging to the genera Marinitoga,... |
| Tipo: Text |
Palavras-chave: Metabolic interactions; 16S rRNA gene; Thermophiles; Bioreactor; Continuous enrichment cultures; Deep sea hydrothermal vent; Microbial diversity. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3885.pdf |
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| Roussel, Erwan; Cambon-bonavita, Marie-anne; Querellou, Joel; Cragg, B; Webster, G; Prieur, D; Parkes, R. |
| Sub-sea-floor sediments may contain two-thirds of Earth's total prokaryotic biomass. However, this has its basis in data extrapolation from ~500-meter to 4-kilometer depths, whereas the deepest documented prokaryotes are from only 842 meters. Here, we provide evidence for low concentrations of living prokaryotic cells in the deepest (1626 meters below the sea floor), oldest (111 million years old), and potentially hottest (~100°C) marine sediments investigated. These Newfoundland margin sediments also have DNA sequences related to thermophilic and/or hyperthermophilic Archaea. These form two unique clusters within Pyrococcus and Thermococcus genera, suggesting unknown, uncultured groups are present in deep, hot, marine sediments (~54° to 100°C). Sequences... |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4209.pdf |
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| Henneke, Ghislaine; Gueguen, Yannick; Flament, Didier; Azam, Philippe; Querellou, Joel; Dietrich, Jacques; Hubscher, Ulrich; Raffin, Jean-paul. |
| The molecular organization of the replication complex in archaea is similar to that in eukaryotes. Only two proteins homologous to subunits of eukaryotic replication factor C (RFC) have been detected in Pyrococcus abyssi (Pab). The genes encoding these two proteins are arranged in tandem. We cloned these two genes and co-expressed the corresponding recombinant proteins in Escherichia coli. Two inteins present in the gene encoding the small subunit (Pab RFC-small) were removed during cloning. The recombinant protein complex was purified by anion-exchange and hydroxyapatite chromatography. Also, the Pab RFC-small subunit could be purified, while the large subunit (Pab RFC-large) alone was completely insoluble. The highly purified Pab RFC complex possessed an... |
| Tipo: Text |
Palavras-chave: PCNA binding domain; Pyrococcus abyssi; Hyperthermophile; Archaea; Replication factor C. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/2002/publication-675.pdf |
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| Rouillon, Christophe; Henneke, Ghislaine; Flament, Didier; Querellou, Joel; Raffin, Jean-paul. |
| DNA replication in Archaea, as in other organisms, involves large protein complexes called replisomes. In the Euryarchaeota subdomain, only two putative replicases have been identified, and their roles in leading and lagging strand DNA synthesis are still poorly understood. In this study, we focused on the coupling of proliferating cell nuclear antigen (PCNA)loading mechanisms with DNA polymerase function in the Euryarchaea Pyrococcus abyssi. PCNA spontaneously loaded onto primed DNA, and replication factor C dramatically increased this loading. Surprisingly, the family B DNA polymerase (Pol B) also increased PCNA loading, probably by stabilizing the clamp on primed DNA via an essential motif. In contrast, on an RNA-primed DNA template, the PCNA/Pol B... |
| Tipo: Text |
Palavras-chave: RF C; PCNA loading; DNA polymerase switching; DNA replication; Archaea. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2638.pdf |
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| Postec, Anne; Le Breton, Claire; Fardeau, Marie-laure; Lesongeur, Francoise; Pignet, Patricia; Querellou, Joel; Ollivier, Bernard; Godfroy, Anne. |
| A novel, thermophilic, anaerobic bacterium that is able to tolerate hydrogen was isolated from a deep-sea hydrothermal chimney collected at the Rainbow field on the Mid-Atlantic Ridge. Cells were rod-shaped and surrounded by a sheath-like outer structure (toga); they were weakly motile by means of a polar flagellum. They appeared singly, in pairs or in short chains. They grew at 35-65 degrees C (optimum 60 degrees C), pH 4.5-8.5 (optimum pH 6.0) and 10-65 g sea salts l(-1) (optimum 30-40 g l(-1)). The isolate was organotrophic, and able to grow on various carbohydrates or complex proteinaceous substrates. Growth was not inhibited under 100% hydrogen or in the presence of 2% oxygen in the gas phase. The isolate reduces sulfur, although sulfur reduction is... |
| Tipo: Text |
Palavras-chave: Anaerobic bacterium; Marinitoga hydrogenitolerans; Thermotogales; Thermophile; Deep sea vent. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-363.pdf |
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| Ishibashi, Jun-ichiro; Lupton, John E.; Yamaguchi, Toshiyuki; Querellou, Joel; Nunoura, Takuro; Takai, Ken. |
| TheValu Fa Ridge (VFR) in the southern Lau Basin—located behind the westward‐dipping Tonga‐Kerrnadec subduction zone—was one of the earliest targets to b e explored for hydrothermal activity in the southwestern Pacific Ocean (Figure l).In 1989, the French‐German dive program NAUTILAU (Nautile‐lan) discovered active hydrothermal fields venting high‐temperature fluids with high acidity accompanied by massive ore deposits in this area [Fbuquet et al., 1993]. In September–October 2004, the SWEEP VENTS (Southwestern Edge of Pacific hydrothermal vents) expedition explored and sampled the hydrothermal systems of the VFR using the deep submergence research vehicle (DSRV) Shinkai 6500. The 2004 Shinkai dives focused on the geobiological and geochemical character of... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00451/56261/57831.pdf |
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| Querellou, Joel. |
| La majorité des enzymes utilisées dans l’industrie provient des bactéries et des levures. Mais les conditions extrêmes dans lesquelles se développent de nombreuses espèces d’archées font que leurs constituants cellulaires possèdent des propriétés et une stabilité propices à leur utilisation en biotechnologie. |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00004/11488/8078.pdf |
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| Postec, Anne; Pignet, Patricia; Cueff-gauchard, Valerie; Schmitt, Anne; Querellou, Joel; Godfroy, Anne. |
| The hyperthermophilic archaeon Thermococcus hydrothermalis was cultivated in continuous culture in a gas-lift bioreactor in the absence of elemental sulphur on both proteinaceous and maltose-containing media. Optimal conditions (pH, temperature and gas flow rate), determined on complex media that yielded maximal growth rate and maximal steady state cell density, were obtained at 80degreesC, pH 6 and gas sparging at 0.2 v v(-1) min(-1). Higher steady state cell densities were obtained on a medium containing maltose and yeast extract. In order to design a defined and minimal media, the nutritional requirements of T hydrothermalis were then investigated using continuous culture in the absence of elemental sulphur in the gas-lift bioreactor. First, the complex... |
| Tipo: Text |
Palavras-chave: Bioreactor; Defined and minimal media; Culture optimisation; Gas lift bioreactor; Thermococcus hydrothermalis. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-365.pdf |
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| Joint, Ian; Mühling, Martin; Querellou, Joel. |
| The potential for using marine microbes for biodiscovery is severely limited by the lack of laboratory cultures. It is a long-standing observation that standard microbiological techniques only isolate a very small proportion of the wide diversity of microbes that are known in natural environments from DNA sequences. A number of explanations are reviewed. The process of establishing laboratory cultures may destroy any cell-to-cell communication that occurs between organisms in the natural environment and that are vital for growth. Bacteria probably grow as consortia in the sea and reliance on other bacteria for essential nutrients and substrates is not possible with standard microbiological approaches. Such interactions should be considered when designing... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00035/14631/11950.pdf |
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| Slobodkina, G. B.; Kolganova, T. V.; Querellou, Joel; Bonch-osmolovskaya, E. A.; Slobodkin, A. I.. |
| A hyperthermophilic, anaerobic, dissimilatory Fe(III)-reducing, facultatively chemolithoautotrophic archaeon (strain SBH6(T)) was isolated from a hydrothermal sample collected from the deepest of the known World Ocean hydrothermal fields, Ashadze field (12 degrees 58' 21 '' N 44 degrees 51' 47 '' W) on the Mid-Atlantic Ridge, at a depth of 4100 m. The strain was enriched using acetate as the electron donor and Fe(III) oxide as the electron acceptor. Cells of strain SBH6(T) were irregular cocci, 0.3-0.5 mu m in diameter. The temperature range for growth was 50-85 degrees C, with an optimum at 81 degrees C. The pH range for growth was 5.0-7.5, with an optimum at pH 6.8. Growth of SBH6(T) was observed at NaCl concentrations ranging from 1 to 6 % (w/v) with an... |
| Tipo: Text |
Palavras-chave: Dissimilatory reduction; Microorganisms; Gradient. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6977.pdf |
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| Alain, Karine; Olagnon, Michel; Desbruyeres, Daniel; Page, Antoine; Barbier, Georges; Juniper, Kim; Querellou, Joel; Cambon-bonavita, Marie-anne. |
| As part of an ongoing examination of microbial diversity associated with hydrothermal vent polychaetes of the family Alvinellidae, we undertook a culture-independent molecular analysis of the bacterial assemblage associated with mucous secretions of the Northeastern Pacific vent polychaete Paralvinella palmiformis. Using a molecular 16S rDNA-based phylogenetic approach, clone libraries were constructed from two samples collected from active sulfide edifices in two hydrothermal vent fields. In both cases, clone libraries were largely dominated by epsilon-Proteobacteria. Phylotypes belonging to the Cytophaga-Flavobacteria and to the Verrucomicrobia were also largely represented within the libraries. The remaining sequences were related to the taxonomic... |
| Tipo: Text |
Palavras-chave: Proteobacteria; 16S rRNA; Microbial diversity; Phylogeny; Hydrothermal vent; Paralvinella palmiformis. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/2002/publication-661.pdf |
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| Postec, Anne; Urios, Laurent; Lesongeur, Francoise; Ollivier, Bernard; Querellou, Joel; Godfroy, Anne. |
| The microflora developing during a continuous enrichment culture from a hydrothermal chimney sample was investigated by molecular methods. The culture was performed in a gas-lift bioreactor under anaerobic conditions, at 90 degrees C and pH 6.5, on a complex medium containing sulfur as the terminal electron acceptor. Archaeal and bacterial diversity was studied. Microorganisms affiliated with the genera Pyrococcus, Marinitoga, and Bacillus were detected through DGGE analysis of 16S rDNA. Additional sequences phylogenetically related to Thermococus and epsilon-Proteobacteria were detected by cloning and sequencing of 16S rDNA from two samples of the enrichment culture. In comparison, the sequences retrieved from cloning analysis from an enrichment culture... |
| Tipo: Text |
Palavras-chave: Sequence alignment; Anaerobic digester; Thermotogales; Thermophile; Deep sea vent. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-364.pdf |
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| Takai, Ken; Miyazaki, Masayuki; Hirayama, Hisako; Nakagawa, Satoshi; Querellou, Joel; Godfroy, Anne. |
| P>Two novel, thermophilic piezophiles, capable of chemolithoautotrophic growth, are successfully cultivated and isolated from a black smoker chimney at the TAG field (Mid Atlantic Ridge: MAR) by using a piezophilic cultivation technique. Both strains (strains 106 and 108) represent dominant cultivated populations of the microbial communities in the chimney surface habitat. Strain 106 represents typically thin, long spiral cells under the piezophilic growth condition but short bent cells under the non-piezophilic condition. It is a strictly chemolithoautotrophic gammaproteobacterium using reduced sulfur compounds as the electron donors, and nitrate and O-2 as the electron acceptors. Based on the 16S rRNA gene sequence, strain 106 would represent a novel... |
| Tipo: Text |
Palavras-chave: Sp. nov.; Ecological signifiance; Hydrostatic pressure; Subsurface biosphere; Base composition; High temperature; Membrane lipids; Gen. nov.; Microorganisms; Diversity. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6652.pdf |
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| Alain, Karine; Callac, Nolwenn; Guegan, Marianne; Lesongeur, Francoise; Crassous, Philippe; Cambon-bonavita, Marie-anne; Querellou, Joel; Prieur, Daniel. |
| A novel strictly anaerobic, thermophilic, sulfur-reducing bacterium, designated PH1209(T), was isolated from an East Pacific Rise hydrothermal vent (13 degrees N) sample and studied using a polyphasic taxonomic approach. Cells were Gram-negative, motile rods (approx. 1.60x0.40 mu m) with a single polar flagellum. Strain PH1209(T) grew at temperatures between 33 and 65 degrees C (optimum 60 degrees C), from pH 5.0 to 8.0 (optimum 6.0-6.5), and between 2 and 4% (w/v) NaCl (optimum 3%). Cells grew chemolithoautotrophically with H-2 as an energy source, So as an electron acceptor and CO2 as a carbon source. Strain PH1209(T) was also able to use peptone and yeast extract as carbon sources. The G+C content of the genomic DNA was 35 mol%. Phylogenetic: analyses... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6585.pdf |
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| Konn, Cecile; Testemale, D.; Querellou, Joel; Holm, N. G.; Charlou, Jean-luc. |
| Experiments on hydrothermal degradation of Pyrococcus abyssi biomass were conducted at elevated pressure (40 MPa) over a 200-450 degrees C temperature range in sapphire reaction cells. Few organic compounds could be detected in the 200 degrees C experiment. This lack was attributed to an incomplete degradation of P. abyssi cells. On the contrary, a wide range of soluble organic molecules were generated at temperatures >= 350 degrees C including toluene, styrene, C-8-C-16 alkyl-benzenes, naphthalene, C-11-C-16 alkyl-naphthalenes, even carbon number C-12-C-18 polycyclic aromatic hydrocarbons, C-15-C-18 alkyl-phenanthrenes and C-8:0-C-16:0 n-carboxylic acids. The effect of time on the final organic composition of the degraded P. abyssi solutions at 350... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00023/13416/10475.pdf |
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| Alain, Karine; Querellou, Joel. |
| Since the invention of the Petri dish, there have been continuous efforts to improve efficiency in microbial cultivation. These efforts were devoted to the attainment for diverse growth conditions, simulation of in situ conditions and achievement of high-throughput rates. As a result, prokaryotes catalysing novel redox reactions as well as representatives of abundant, but not-yet cultured taxa, were isolated. Significant insights into microbial physiology have been made by studying the small number of prokaryotes already cultured. However, despite these numerous breakthroughs, microbial cultivation is still a low-throughput process. The main hindrance to cultivation is likely due to the prevailing lack of knowledge on targeted species. In this review, we... |
| Tipo: Text |
Palavras-chave: High throughput cultivation; Cell cell communication; Microbial community; Metabolism; Isolation; Culture. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6820.pdf |
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| Registros recuperados: 27 | |
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