Consulta: creatorFacets:"Simon-colin, Christelle"
Registros recuperados: 10
Data/hora: 07/06/2024 03:31:23

Study of biosorption of copper and silver by marine bacterial exopolysaccharides
Provedor de dados: 5
Autores: Deschatre, Marine; Ghillebaert, F.; Guezennec, Jean; Simon-colin, Christelle.
Metal bioremediation was studied by biosorption of analytical grade copper Cu(II) and silver Ag(I) by an exopolysaccharide (EPS) produced by marine bacteria from French Polynesia. Colorimetric analysis showed that EPS was composed of neutral sugars, uronic acids, acetate and especially high sulfate amount (29%). Metal biosorption experiments were conducted in batch process. Results showed that the maximum sorption capacities calculated according to Langmuir model were 400 mg g(-1) EPS (6.29 mmol g(-1)) and 256 mg g(-1) EPS (2.38 mmol g(-1)) for Cu(II) and Ag(I), respectively. The influence of pH, biosorbent concentration, ionic strength on EPS biosorption capacities was investigated. Results showed that bacterial EPS can be considered as very promising for...
Tipo: Text
Palavras-chave: Biosorption; Bacterial exopolysaccharides; Copper and silver removal; Bioremediation.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00601/71336/69766.pdf

Biosynthesis of medium chain length poly-3-hydroxyalkanoates by Pseudomonas guezennei from various carbon sources
Provedor de dados: 5
Autores: Simon-colin, Christelle; Raguenes, Gerard; Costa, Bernard; Guezennec, Jean.
The biosynthesis of poly-(3-hydroxyalkanoates) (PHAs) by Pseudomonas guezennei using glucose and/or fatty acids with chain-length from 3 to 18 carbon atoms as carbon sources was investigated. Glucose, acetate, pyruvate, propionate, valerate, hexanoate, heptanoate, octanoate, decanoate, and oleic acid were supplemented in the mineral medium as the sole carbon source or as a mixture for PHAs accumulation. Chemical composition of the resulting PHAs was analysed by coupled gas chromatography mass spectroscopy (GCMS), Fourier Transform Infrared Spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). PHAs contained up to 10 different types of 3-hydroxyalkanoic acid units, including saturated 3-hydroxyacids from C4 to C14, and unsaturated monomers...
Tipo: Text
Palavras-chave: Carbon substrates; Pseudomonas guezennei; Polymer characterization; Polyhydroxyalkanoates.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6115.pdf

Sorption of Copper(II) and Silver(I) by Four Bacterial Exopolysaccharides
Provedor de dados: 5
Autores: Deschatre, Marine; Ghillebaert, F.; Guezennec, Jean; Simon-colin, Christelle.
Metal remediation was studied by the sorption of analytical grade copper Cu(II) and silver Ag(I) by four exopolysaccharides (EPS) produced by marine bacteria. Colorimetric analysis showed that these EPS were composed of neutral sugars, uronic acids (&gt;20 %), acetate, and sulfate (29 %). Metal sorption experiments were conducted in batch process. Results showed that the maximum sorption capacities calculated according to Langmuir model were 400 mg g−1 EPS (6.29 mmol g−1) and 333 mg g−1 EPS (3.09 mmol g−1) for Cu(II) and Ag(I), respectively. Optimum pH values of Ag(I) sorption were determined as 5.7. Experiment results also demonstrated the influence of initial silver concentration and EPS concentrations. Microanalyzing coupled with scanning electron...
Tipo: Text
Palavras-chave: Sorption; Bacterial exopolysaccharide; Copper and silver removal; Bioremediation.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00171/28222/27464.pdf

Partial characterization of an exopolysaccharide secreted by a marine bacterium, Vibrio neocaledonicus sp nov., from New Caledonia
Provedor de dados: 5
Autores: Chalkiadakis, Eletherios; Dufourcq, R.; Schmitt, Sophie; Brandily, Christophe; Kervarec, N.; Coatanea, Denis; Amir, H.; Loubersac, Lionel; Chanteau, S.; Guezennec, Jean; Dupont-rouzeyrol, M.; Simon-colin, Christelle.
Aims Exopolysaccharides (EPS) are industrially valuable molecules with numerous useful properties. This study describes the techniques used for the identification of a novel Vibrio bacterium and preliminary characterization of its EPS. Methods and Results Bioprospection in marine intertidal areas of New Caledonia followed by screening for EPS producing brought to selection of the isolate NC470. Phylogenetic analysis (biochemical tests, gene sequencing and DNADNA relatedness) permitted to identify NC470 as a new member of the Vibrio genus. The EPS was produced in batch fermentation, purified using the ultrafiltration process and analysed by colorimetry, Fourier Transform Infrared spectroscopy, gas chromatography, Nuclear Magnetic Resonance and HPLC-size...
Tipo: Text
Palavras-chave: Biopolymers; Biotechnology; Exopolysaccharide; Fermentation biotechnology.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00144/25501/24036.pdf

Floridoside extracted from the red alga Mastocarpus stellatus is a potent activator of the classical complement pathway
Provedor de dados: 5
Autores: Courtois, Anthony; Simon-colin, Christelle; Boisset, Claire; Berthou, Christian; Deslandes, Eric; Guezennec, Jean; Bordron, Anne.
Many biological properties of algae have been found to have useful applications in human health, particularly in the fields of oncology and immunology. Floridoside, extracted from the red alga Mastocarpus stellatus, has a structure similar to the xenoantigen Gal alpha 1-3 Gal. This xenoantigen has been described to induce a high immune response in human xenografts and is mediated by natural anti-gal antibodies that activate the classical complement pathway. Based on this property, we analyzed the potential activities of floridoside on the immune system. We demonstrated that floridoside activates a complement cascade via the classical complement pathway, through the recruitment and activation of natural IgM. This algal molecule could represent an important...
Tipo: Text
Palavras-chave: Complement system; Immunomodulation; Marine algae; Alpha galactosyl glycerol.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6248.pdf

Investigations into the uptake of copper, iron and selenium by a highly sulphated bacterial exopolysaccharide isolated from microbial mats
Provedor de dados: 5
Autores: Moppert, Xavier; Le Costaouec, Tinaig; Raguenes, Gerard; Courtois, Anthony; Simon-colin, Christelle; Crassous, Philippe; Costa, Bernard; Guezennec, Jean.
A bacterium isolated from microbial mats located on a polynesian atoll produced a high molecular weight (3,000 kDa) and highly sulphated exopolysaccharide. Previous studies showed that the chemical structure of this EPS consisted of neutral sugars, uronic acids, and high proportions of acetate and sulphate groups. The copper- and iron-binding ability of the purified pre-treated native EPS was investigated. Results showed that this EPS had a very high affinity for both copper (9.84 mmol g(-1) EPS) and ferrous iron (6.9 mmol g(-1) EPS). Amazingly, this EPS did not show any affinity for either ferric ions or selenium salts. This finding is one of the first steps in assessing the biotechnological potential of this polysaccharide.
Tipo: Text
Palavras-chave: Sulphated exopolysaccharide; Microbial mats; Iron; Copper; Binding capacity.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6397.pdf

A novel mcl-PHA produced on coprah oil by Pseudomonas guezennei biovar. tikehau, isolated from a "kopara" mat of French Polynesia
Provedor de dados: 5
Autores: Simon-colin, Christelle; Raguenes, Gerard; Crassous, Philippe; Moppert, X; Guezennec, Jean.
Pseudomonasguezennei biovar. tikehau was isolated from a microbial mat on the atoll of Tikehau in French Polynesia, and is able to synthesize medium chain length poly-beta-hydroxyalkanaote copolymers when grown on coprah oil. A two-step cultivation process was used and the biosynthesis of PHAs was followed along 52 h by regular culture sampling. The polyester was purified from freeze-dried cells and analysed by nuclear magnetic resonance (NMR), Fourier transform infra red (FTIR), and gas chromatography mass spectrometries. The copolyester produced by P. guezennei biovar. tikehau from coprah oil mainly consisted of saturated monomers, i.e. 3-hydroxyoctanoate (3HO) and 3-hydroxydecanoate (3HD), and the monomeric composition of the polyester did not change...
Tipo: Text
Palavras-chave: Polyhydroxyalkanaote; PHAs; Pseudomonas; "kopara"; Microbial mat.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6119.pdf

Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production
Provedor de dados: 5
Autores: Simon-colin, Christelle; Gueguen, Yannick; Bachere, Evelyne; Kouzayha, Achraf; Saulnier, Denis; Gayet, Nicolas; Guezennec, Jean.
Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with...
Tipo: Text
Palavras-chave: Pearl oyster; Exopolysaccharide; Tachyplesin; Antimicrobial.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00275/38599/37128.pdf

A novel mcl PHA-producing bacterium, Pseudomonas guezennei sp nov, isolated from a 'kopara' mat located in Rangiroa, an atoll of French Polynesia
Provedor de dados: 5
Autores: Simon-colin, Christelle; Alain, Karine; Colin, Sebastien; Cozien, Joelle; Costa, B; Guezennec, Jean; Raguenes, Gerard.
Aims: The aim of the present study was to describe an aerobic, mesophilic and heterotrophic bacterium, designated RA26, able to produce a medium-chain-length polyhydroxyalkanoate (PHA). It was isolated from a French Polynesian bacterial mat located in the atoll of Rangiroa.   Methods and Results: This micro-organism, on the basis of the phenotypical features and genotypic investigations can be clearly assigned to the Pseudomonas genus and the name of Pseudomonas guezennei is proposed. Optimal growth occurs between 33 and 37 degrees C, at a pH between 6 4 and 7 1 and at ionic strength of 15 g 1(-1) of sea salts. The G+C content of DNA is 63.2%. Under laboratory conditions, this bacterium produced a novel, medium-chain-length PHA, mainly composed of...
Tipo: Text
Palavras-chave: Pseudomonas; Polyhydroxyalkanaote; Microbial mat; Kopara.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-3858.pdf

Microbial mats in French Polynesia and their biotechnological applications
Provedor de dados: 5
Autores: Guezennec, Jean; Moppert, Xavier; Raguenes, Gerard; Richert, Laurent; Costa, Bernard; Simon-colin, Christelle.
It is well known that microorganisms well-adapted to survival in extreme ecosystems could be considered as new sources of biomolecules that have biotechnological importance. On French Polynesian atolls, microbial mats are developing in water ponds exposed to fluctuations in physical and chemical parameters. In these microbial mats, which are called "kopara" by the inhabitants, bacteria coexist with cyanobacteria, and a synergistic relationship may exist between these two types of living microorganisms. A large number of cyanobacteria and bacteria have been isolated from different mats. Under laboratory conditions, these microorganisms were shown to produce various exopolymers, including exopolysaccharides and poly-beta-hydroxyalkanoates, along with...
Tipo: Text
Palavras-chave: Microbial mats; Kopara; Biopolymers; Exopolysaccharides; Poly-beta-hydroxyalkanoates.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00029/14058/11423.pdf