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| Landreau, M.; Duthoit, Frederique; Roussel, Erwan; Schonherr, S.; Georges, Myriam; Godfroy, Anne; Le Blay, G.. |
| Cultivation in a bioreactor of immobilized deep-sea hydrothermal microbial community was tested in order to assess the stability and reactivity of this new system. A community composed of 8 hydrothermal strains was entrapped in a polymer matrix that was used to inoculate a continuous culture in a gas-lift bioreactor. The continuous culture was performed for 41 days at successively 60°C, 55°C, 60°C, 85°C and 60°C, at pH 6.5, in anaerobic condition and constant dilution rate. Oxic stress and pH variations were tested at the beginning of the incubation. Despite these detrimental conditions, 3 strains including 2 strict anaerobes were maintained in the bioreactor. High cell concentrations (3 × 108 cells mL−1) and high ATP contents were measured in both liquid... |
| Tipo: Text |
Palavras-chave: Immobilization; Anaerobiosis; Marine (hyper)thermophiles; Continuous culture. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00347/45851/45516.pdf |
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| Alain, Karine; Callac, Nolwenn; Ciobanu, Maria Cristina; Reynaud, Yann; Duthoit, Frederique; Jebbar, Mohamed. |
| Extracting DNA from deep subsurface sediments is challenging given the complexity of sediments types, low bio-masses, resting structures (spores, cysts) frequently encountered in deep sediments, and the potential presence of enzymatic inhibitors. Promising results for cell lysis efficiency were recently obtained by use of a cryogenic mill (Lipp et al., 2008). These findings encouraged us to devise a DNA extraction protocol using this tool. Thirteen procedures involving a combination of grinding in liquid nitrogen (for various durations and beating rates) with different chemical solutions (phenol, chloroform, SDS, sarkosyl, proteinase, GTC), or with use of DNA recovery kits (MagExtractor (R)) were compared. Effective DNA extraction was evaluated in terms of... |
| Tipo: Text |
Palavras-chave: Sediment; DNA extraction; Deep subsurface biosphere. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00056/16691/14364.pdf |
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| Landreau, M.; Duthoit, Frederique; Claeys-bruno, M.; Vandenabeele-trambouze, O.; Aubry, T.; Godfroy, Anne; Le Blay, Gwenaelle. |
| Aims The aims of this study were (i) to develop a protocol for the entrapment of anaerobic (hyper)thermophilic marine micro-organisms; (ii) to test the use of the chosen polymers in a range of physical and chemical conditions and (iii) to validate the method with batch cultures. Methods and Results The best conditions for immobilization were obtained at 80°C with gellan and xanthan gums. After 5-week incubation, beads showed a good resistance to all tested conditions except those simultaneously including high temperature (100°C), low NaCl (<0∙5 mol l−1) and extreme pH (4/8). To confirm the method efficiency, batch cultures with immobilized Thermosipho sp. strain AT1272 and Thermococcus kodakarensis strain KOD1 showed an absence of detrimental effect... |
| Tipo: Text |
Palavras-chave: (hyper)thermophilic marine micro-organisms; Anaerobiosis; Entrapment; Gellan; Immobilization; Xanthan. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00332/44352/44000.pdf |
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| Gaboyer, Frederic; Tindall, Brian J.; Ciobanu, Maria Cristina; Duthoit, Frederique; Le Romancer, Marc; Alain, Karine. |
| A novel Gram-stain-negative, strictly aerobic, heterotrophic bacterium, designated 306(T), was isolated from near-surface (109 cm below the sea floor) sediments of the Gulf of Lions, in the Mediterranean Sea. Strain 306(T) grew at temperatures between 4 and 32 degrees C (optimum 17-22 degrees C), from pH 6.5 to 9.0 (optimum 8.0-9.0) and between 0.5 and 6.0% (w/v) NaCl (optimum 2.0%). Its DNA G+C content was 58.8 mol%. On the basis of 16S rRNA gene sequence similarity, the novel isolate belongs to the class Alphaproteobacteria and is related to the genus Phaeobacter. It shares 98.7% 16S rRNA sequence identity with Phaeobacter arcticus, its closest phylogenetic relative. It contained Q-10 as the only respiratory quinone, C-18:1 omega 7c and C-16:0 as major... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00166/27750/25981.pdf |
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