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| Registros recuperados: 15 | |
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| Plouviez, Sophie; Faure, Baptiste; Le Guen, Dominique; Lallier, Francois; Bierne, Nicolas; Jollivet, Didier. |
| Comparative phylogeography of deep-sea hydrothermal vent species has uncovered several genetic breaks between populations inhabiting northern and southern latitudes of the East Pacific Rise. However, the geographic width and position of genetic clines are variable among species. In this report, we further characterize the position and strength of barriers to gene flow between populations of the deep-sea vent mussel Bathymodiolus thermophilus. Eight allozyme loci and DNA sequences of four nuclear genes were added to previously published sequences of the cytochrome c oxidase subunit I gene. Our data confirm the presence of two barriers to gene flow, one located at the Easter Microplate (between 21 degrees 33'S and 31 degrees S) recently described as a hybrid... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00185/29622/28006.pdf |
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| Bierne, Nicolas; Boudry, Pierre; Lapegue, Sylvie; Bonhomme, Francois; Faure, M; Sauvage, Christopher; Moraga, D; Boutet, Isabelle; David, Elise; Jollivet, Didier; Tanguy, Arnaud; Faure, Baptiste; David, Patrice. |
| For a long time, population geneticists have had to content themselves with analysing neutral markers to infer selection processes indirectly. The recent improvement of sequencing tools now enables them to analyse the variations of a large number of genes and therefore to spot the genes, or the amino acids, which are under the direct influence of the selection (Yang & Bielawski, 2000). In order to analyse the selection processes acting on the mutations and discriminate the different factors acting on their evolution (genetic selection or drift), it is essential to compare polymorphism data between genomes of the same species/population and divergence data between species/populations (Kimura, 1983). Recently, polymorphism data has become available for a... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/rapport-6489.pdf |
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| Tasiemski, Aurelie; Jung, Sascha; Boidin-wichlacz, Celine; Jollivet, Didier; Cuvillier-hot, Virginie; Pradillon, Florence; Vetriani, Costantino; Hecht, Oliver; Soennichsen, Frank D.; Gelhaus, Christoph; Hung, Chien-wen; Tholey, Andreas; Leippe, Matthias; Groetzinger, Joachim; Gaill, Francoise. |
| The emblematic hydrothermal worm Alvinella pompejana is one of the most thermo tolerant animal known on Earth. It relies on a symbiotic association offering a unique opportunity to discover biochemical adaptations that allow animals to thrive in such a hostile habitat. Here, by studying the Pompeii worm, we report on the discovery of the first antibiotic peptide from a deep-sea organism, namely alvinellacin. After purification and peptide sequencing, both the gene and the peptide tertiary structures were elucidated. As epibionts are not cultivated so far and because of lethal decompression effects upon Alvinella sampling, we developed shipboard biological assays to demonstrate that in addition to act in the first line of defense against microbial invasion,... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00219/33052/31517.pdf |
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| Holder, Thomas; Basquin, Claire; Ebert, Judith; Randel, Nadine; Jollivet, Didier; Conti, Elena; Jekely, Gaspar; Bono, Fulvia. |
| Background: Alvinella pompejana is an annelid worm that inhabits deep-sea hydrothermal vent sites in the Pacific Ocean. Living at a depth of approximately 2500 meters, these worms experience extreme environmental conditions, including high temperature and pressure as well as high levels of sulfide and heavy metals. A. pompejana is one of the most thermotolerant metazoans, making this animal a subject of great interest for studies of eukaryotic thermoadaptation. Results: In order to complement existing EST resources we performed deep sequencing of the A. pompejana transcriptome. We identified several thousand novel protein-coding transcripts, nearly doubling the sequence data for this annelid. We then performed an extensive survey of previously established... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00185/29627/28001.pdf |
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| Cascella, Kevin; Jollivet, Didier; Papot, Claire; Leger, Nelly; Corre, Erwan; Ravaux, Juliette; Clark, Melody S.; Toullec, Jean-yves. |
| Background A comparative thermal tolerance study was undertaken on two sister species of Euphausiids (Antarctic krills) Euphausia superba and Euphausia crystallorophias. Both are essential components of the Southern Ocean ecosystem, but occupy distinct environmental geographical locations with slightly different temperature regimes. They therefore provide a useful model system for the investigation of adaptations to thermal tolerance. Methodology/Principal Finding Initial CTmax studies showed that E. superba was slightly more thermotolerant than E. crystallorophias. Five Hsp70 mRNAs were characterized from the RNAseq data of both species and subsequent expression kinetics studies revealed notable differences in induction of each of the 5 orthologues... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00293/40445/39081.pdf |
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| Chevaldonne, Pierre; Jollivet, Didier; Vangriesheim, Annick; Desbruyeres, Daniel. |
| Deep-sea hydrothermal-vent habitats are typically linear, discontinuous, and short-lived. Some of the vent fauna such as the endemic polychaete family Alvinellidae are thought to lack a planktotrophic larval stage and therefore not to broadcast-release their offspring. The genetic evidence points to exchanges on a scale that seems to contradict this type of reproductive pattern. However, the rift valley may topographically rectify the bottom currents, thereby facilitating the dispersal of propagules between active vent sites separated in some cases by 10s of kilometers or more along the ridge axis. A propagule flux model based on a matrix of intersite distances, long-term current-meter data, and information on the biology and ecology of Alvinellidae was... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00337/44780/44597.pdf |
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| Jollivet, Didier; Mary, Jean; Gagniere, Nicolas; Tanguy, Arnaud; Fontanillas, Eric; Boutet, Isabelle; Hourdez, Stephane; Segurens, Beatrice; Weissenbach, Jean; Poch, Olivier; Lecompte, Odile. |
| Taking advantage of the massive genome sequencing effort made on thermophilic prokaryotes, thermal adaptation has been extensively studied by analysing amino acid replacements and codon usage in these unicellular organisms. In most cases, adaptation to thermophily is associated with greater residue hydrophobicity and more charged residues. Both of these characteristics are positively correlated with the optimal growth temperature of prokaryotes. In contrast, little information has been collected on the molecular 'adaptive' strategy of thermophilic eukaryotes. The Pompeii worm A. pompejana, whose transcriptome has recently been sequenced, is currently considered as the most thermotolerant eukaryote on Earth, withstanding the greatest thermal and chemical... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00129/24008/21976.pdf |
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| Matabos, Marjolaine; Jollivet, Didier. |
| The current distribution ranges of vent species result from the complex tectonic history of oceanic ridges. A growing number of DNA barcode studies report the presence of cryptic species across geological discontinuities that offset ridge systems and have gradually helped to draw a more precise picture of the historical migration pathways of vent fauna. We reexamined the phylogeny of species within the Lepetodrilus elevatus complex along the East Pacific Rise (EPR) ridge system in the light of new samples from the Galápagos Rift and the Guaymas Basin. Our analyses of mitochondrial cytochrome c oxidase subunit I gene sequences, coupled with morphological data, highlight the occurrence of a distinct lineage along the Galápagos Rift and offer new insight into... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00479/59048/61792.pdf |
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| Chevaldonne, Pierre; Jollivet, Didier; Desbruyeres, Daniel; Lutz, Richard; Vrijenhoek, Robert. |
| Introduction : The evolutionary age of some of the hydrothermal vent taxa have recently become a highly debated issue. Vestimentiferan worms (= siboglinid polychaetes) in particular, have been claimed to be as old as 430 million years based on the occurrence of fossilized tubes resembling those of currently known Vestimentifera (Little et al., 1997), while other authors, based on molecular data, have claimed they must be younger than 100 million years old (Black et al, 1997; Halanych et al., 1998). One explanation for this apparent discrepancy might be that tubes, such as those found in the Silurian fossil vent communities, did not belong to vestimentiferans, but rather to other tube-dwelling polychaetes. However, it is also possible that the choice of the... |
| Tipo: Text |
Palavras-chave: Allopatric speciation; Polychaetes; Polychaetes; Hydrothermal vent. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-895.pdf |
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| Shillito, Bruce; Jollivet, Didier; Sarradin, Pierre-marie; Rodier, Philippe; Lallier, François; Desbruyeres, Daniel; Gaill, Françoise. |
| For the first time, in vivo heat-exposure experiments were conducted on the hydrothermal vent polychaete Hesiolyra bergi from the hottest part of the vent biotope. Using a pressurised incubator equipped with video-facilities, we found that H. bergi, which forages around and in the tubes of the thermophilic Alvinella sp., became hyperactive once temperature exceeded 35 degreesC and further lost co-ordination in the 41 to 46 degreesC interval, just before death occurred. Another exposure experiment at 39 degreesC for 3 to 4 h led to 80 % mortality (max) 9 h after heat shock, and 100 % thereafter. In view of the much higher temperatures recorded in this organism's habitat, these results suggest that tolerance to high temperatures (exceeding 40 degreesC) is... |
| Tipo: Text |
Palavras-chave: IPOCAMP; Adaptation to heat; Behaviour; Hydrothermal vents. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/2001/publication-811.pdf |
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| Chevaldonne, P; Jollivet, Didier. |
| Biomass is a poorly documented parameter of the hydrothermal ecosystem, partly due to the difficulties in estimating it. Because the hydrothermal alvinellid polychaete worms mostly live in tubes, and on very irregular surfaces difficult to sample, an original biomass estimation method based on video analysis was proposed and tested on populations of the East Pacific Rise at 13-degrees-N. The area covered by the 3 main alvinellid species was accurately estimated from geometrical calculations in oblique-angle conditions, requiring only 3 object measurements on the monitor screen. The total density of alvinellids was estimated on video by modelling the pattern of worm movements in and out of their tubes. The Richards function was found appropriate to model... |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00193/30395/29003.pdf |
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| Bruno, Renato; Maresca, Marc; Canaan, Stéphane; Cavalier, Jean-françois; Mabrouk, Kamel; Boidin-wichlacz, Céline; Olleik, Hamza; Zeppilli, Daniela; Brodin, Priscille; Massol, François; Jollivet, Didier; Jung, Sasha; Tasiemski, Aurélie. |
| Antimicrobial peptides (AMPs) are natural antibiotics produced by all living organisms. In metazoans, they act as host defense factors by eliminating microbial pathogens. But they also help to select the colonizing bacterial symbionts while coping with specific environmental challenges. Although many AMPs share common structural characteristics, for example having an overall size between 10–100 amino acids, a net positive charge, a γ-core motif, or a high content of cysteines, they greatly differ in coding sequences as a consequence of multiple parallel evolution in the face of pathogens. The majority of AMPs is specific of certain taxa or even typifying species. This is especially the case of annelids (ringed worms). Even in regions with extreme... |
| Tipo: Text |
Palavras-chave: Antibiotics; Annelids; Nematodes; AMP; Extremophiles. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00511/62307/66556.pdf |
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| Registros recuperados: 15 | |
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