Consulta: creatorFacets:"Querellou, Joel"
Registros recuperados: 27
Data/hora: 01/06/2024 16:20:29

Desulfurobacterium crinifex sp.nov., a novel thermophilic, pinkish-streamer forming, chemolithoautotrophic bacterium isolated from a Juan de Fuca Ridge hydrothermal vent and amendment of the genus Desulfurobacterium
Provedor de dados: 5
Autores: Alain, Karine; Rolland, Sophie; Crassous, Philippe; Lesongeur, Francoise; Zbinden, Magali; Le Gall, Christian; Godfroy, Anne; Page, Antoine; Juniper, S Kim; Cambon-bonavita, Marie-anne; Duchiron, Francis; Querellou, Joel.
A novel thermophilic, chemolithoautotrophic T bacterium, designated as NE1206(T), was isolated from a Juan de Fuca Ridge hydrothermal vent sample (tubes of the annelid polychaete Paralvinella sulfincola attached to small pieces of hydrothermal chimney). The cells were rod-shaped (1.2-3.5x0.4-0.7 mum), occurring as single motile rods or forming macroscopic aggregates visible as pinkish to brownish streamers. The new isolate was anaerobic. It grew between 50 and 70 degreesC (optimum 60-65 degreesC doubling time approximately 1 h 15 min at 60 degreesC), between pH 5.0 and 7.5 (optimum pH around 6.0-6.5) and at sea salts concentrations between 20 and 40 g l(-1) (optimum 30 g l(-1)). Cells grew chemolithoautotrophically in an H-2/CO2 atmosphere (80/20, v/v; 200...
Tipo: Text
Palavras-chave: Thermophile; Nitrate reducing; Lithotroph; Desulfurobacterium crinifex; Deep sea hydrothermal vent; Cell networks.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-663.pdf

Culturing marine bacteria - an essential prerequisite for biodiscovery
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00035/14631/11950.pdf

DNA polymerase switching on homotrimeric PCNA at the replication fork of the euryarchaea Pyrococcus abyssi
Provedor de dados: 5
Autores: 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

Binding to PCNA in Euryarchaeal DNA Replication Requires Two PIP Motifs for DNA Polymerase D and One PIP Motif for DNA Polymerase B
Provedor de dados: 5
Autores: Castrec, Benoit; Rouillon, Christophe; Henneke, Ghislaine; Flament, Didier; Querellou, Joel; Raffin, Jean-paul.
Replicative DNA polymerases possess a canonical C-terminal proliferating cell nuclear antigen (PCNA)-binding motif termed the PCNA-interacting protein (PIP) box. We investigated the role of the PIP box on the functional interactions of the two DNA polymerases, PabPol B (family B) and PabPol D (family D), from the hyperthermophilic euryarchaeon Pyrococcus abyssi, with its cognate PCNA. The PIP box was essential for interactions of PabPol B with PCNA, as shown by surface plasmon resonance and primer extension studies. In contrast, binding of PabPol D to PCNA was affected only partially by removing the PIP motif. We identified a second palindromic PIP box motif at the N-terminus of the large subunit of PabPol D that was required for the interactions of PabPol...
Tipo: Text
Palavras-chave: Archaea; PIP box; PCNA binding motifs; DNA polymerases; DNA replication.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7317.pdf

Des enzymes pour l'industrie
Provedor de dados: 5
Autores: Querellou, Joel; Gueguen, Yannick; Barbier, Georges; Dietrich, Jacques.
Tipo: Text
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00092/20334/18037.pdf

Cultivating the uncultured: limits, advances and future challenges
Provedor de dados: 5
Autores: 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

Marinitoga hydrogenitolerans sp nov., a novel member of the order Thermotogales isolated from a black smoker chimney on the Mid-Atlantic Ridge
Provedor de dados: 5
Autores: 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

Biotechnologie des archées
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00004/11488/8078.pdf

The hyperthermophilic euryarchaeota Pyrococcus abyssi likely requires the two DNA polymerases D and B for DNA replication
Provedor de dados: 5
Autores: 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

Isolation and physiological characterization of two novel, piezophilic, thermophilic chemolithoautotrophs from a deep-sea hydrothermal vent chimney
Provedor de dados: 5
Autores: Takai, Ken; Miyazaki, Masayuki; Hirayama, Hisako; Nakagawa, Satoshi; Querellou, Joel; Godfroy, Anne.
P&gt;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

Extending the sub-sea-floor biosphere
Provedor de dados: 5
Autores: 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
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4209.pdf

Comparison of microbial communities associated with three Atlantic ultramafic hydrothermal systems
Provedor de dados: 5
Autores: 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&gt;11; T&lt;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

Geoglobus acetivorans sp nov., an iron(III)-reducing archaeon from a deep-sea hydrothermal vent
Provedor de dados: 5
Autores: 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

The heterodimeric primase from the euryarchaeon Pyrococcus abyssi: A multifunctional enzyme for initiation and repair?
Provedor de dados: 5
Autores: Le Breton, Magali; Henneke, Ghislaine; Norais, C; Flament, Didier; Myllykallio, H; Querellou, Joel; Raffin, Jean-paul.
We report on the characterization of the DNA primase complex of the hyperthermophilic archaeon Pyrococcus abyssi (Pab). The Pab DNA primase complex is composed of the proteins Pabp41 and Pabp46, which show sequence similarities to the p49 and p58 subunits, respectively, of the eukaryotic polymerase alpha-primase complex. Both subunits were expressed, purified, and characterized. The Pabp41 subunit alone had no RNA synthesis activity but could synthesize long (up to 3 kb) DNA strands. Addition of the Pabp46 subunit increased the rate of DNA synthesis but decreased the length of the DNA fragments synthesized and conferred RNA synthesis capability. Moreover, in our experimental conditions, Pab DNA primase had comparable affinities for ribonucleotides and...
Tipo: Text
Palavras-chave: Strand displacement; Gap filling; DNA primase; Archaea; DNA replication.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3520.pdf

Nautilia abyssi sp nov., a thermophilic, chemolithoautotrophic, sulfur-reducing bacterium isolated from an East Pacific Rise hydrothermal vent
Provedor de dados: 5
Autores: 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
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6585.pdf

Phylogenetic characterization of the bacterial assemblage associated with mucous. secretions of the hydrothermal vent polychaete Paralvinella palmiformis
Provedor de dados: 5
Autores: 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

Deep-sea genetic resources
Provedor de dados: 5
Autores: Desbruyere, D; Arnaud-haond, Sophie; Fabri, Marie-claire; Guezennec, Jean; Querellou, Joel.
Two third of our Planet are covered by oceans more than 3,000m deep (~ 307 millions km2) and the mean depth of the sea is approximately 3,800m. The volume of the deep ocean (aphotic) is about 1,280 Millions of km3 while the volume of terrestrial ecosystems is only 125 Millions of km3. Therefore, the deep-sea ecosystem is by far the largest complex biome on the Earth. However, it suffers from a general disinterest of the public and decision makers due to its remoteness and inaccessibility. Edward Forbes "azoic theory" is still deeply rooted in most people brains and during public conferences, a large part of the audience being still amazed to hear that macroscopic life does exist in the deepest part of the sea floor (11,000m depth).
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00153/26452/24558.pdf

Replication factor C from the hyperthermophilic archaeon Pyrococcus abyssi does not need ATP hydrolysis for clamp-loading and contains a functionally conserved RFC PCNA-binding domain
Provedor de dados: 5
Autores: 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

Optimisation of growth conditions for continuous culture of the hyperthermophilic archaeon Thermococcus hydrothermalis and development of sulphur-free defined and minimal media
Provedor de dados: 5
Autores: 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

New insight into the contributions of thermogenic processes and biogenic sources to the generation of organic compounds in hydrothermal fluids
Provedor de dados: 5
Autores: 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 &gt;= 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
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00023/13416/10475.pdf

Caminicella sporogenes gen. nov., sp nov., a novel thermophilic spore-forming bacterium isolated from an East-Pacific Rise hydrothermal vent
Provedor de dados: 5
Autores: Alain, Karine; Pignet, Patricia; Zbinden, M; Quillevere, M; Duchiron, F; Donval, Jean-pierre; Lesongeur, Francoise; Raguenes, Gerard; Crassous, Philippe; Querellou, Joel; Cambon-bonavita, Marie-anne.
A novel thermophilic, anaerobic, strictly chemoorganoheterotrophic bacterium, designated as AM1114(T), was isolated from a deep-sea hydrothermal vent sample from the East-Pacific Rise (EPR 13degrees N). The cells were long (3-10 mum) rods, motile with peritrichous flagella, and exhibited a Gram-negative cell wall ultrastructure. In the late stationary phase of growth, cells formed an ovoid, refractile, terminal endospore. They grew at 45-65 degreesC inclusive (optimum 55-60 degreesC; doubling time approx. 45 min), at pH 4.5-8.0 inclusive (optimum pH 7.5-8.0) and at sea salt concentrations of 20-60 g l(-1) inclusive (optimum 25-30 g l(-1)). Strain AM1114(T) was an obligately heterotrophic bacterium able to ferment a mixture of 20 amino acids, complex...
Tipo: Text
Palavras-chave: Caminicella sporogenes; Clostridiales; Thermophile; Deep sea hydrothermal vent.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/publication-528.pdf

Pyrococcus CH1, an obligate piezophilic hyperthermophile: extending the upper pressure-temperature limits for life
Provedor de dados: 5
Autores: 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

Intrinsic properties of the two replicative DNA polymerases of Pyrococcus abyssi in replicating abasic sites: possible role in DNA damage tolerance?
Provedor de dados: 5
Autores: Palud, Adeline; Villani, Giuseppe; L'Haridon, Stephane; Querellou, Joel; Raffin, Jean-paul; Henneke, Ghislaine.
Spontaneous and induced abasic sites in hyperthermophiles DNA have long been suspected to occur at high frequency. Here, Pyrococcus abyssi was used as an attractive model to analyse the impact of such lesions onto the maintenance of genome integrity. We demonstrated that endogenous AP sites persist at a slightly higher level in P. abyssi genome compared with Escherichia coli. Then, the two replicative DNA polymerases, PabpolB and PabpolD, were characterized in presence of DNA containing abasic sites. Both Pabpols had abortive DNA synthesis upon encountering AP sites. Under running start conditions, PabpolB could incorporate in front of the damage and even replicate to the full-length oligonucleotides containing a specific AP site, but only when present at...
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6113.pdf

Deferribacter autotrophicus sp nov., an iron(III)-reducing bacterium from a deep-sea hydrothermal vent
Provedor de dados: 5
Autores: 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

Continuous enrichment cultures: insights into prokaryotic diversity and metabolic interactions in deep-sea vent chimneys
Provedor de dados: 5
Autores: 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

Continuous enrichment culture and molecular monitoring to investigate the microbial diversity of thermophiles inhabiting deep-sea hydrothermal ecosystems
Provedor de dados: 5
Autores: 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

Expedition reveals changes in Lau Basin Hydrothermal System
Provedor de dados: 5
Autores: 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
Ano: 2006
URL: http://archimer.ifremer.fr/doc/00451/56261/57831.pdf