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| Registros recuperados: 40 | |
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| Colliec-jouault, Sylvia; Zanchetta, P; Helley, D; Ratiskol, Jacqueline; Sinquin, Corinne; Fischer, A. M.; Guezennec, Jean. |
| Bacterial polysaccharides offer fascinating potential applications for the pharmaceutical industry. Although many known marine bacteria produce exopolysaccharides (EPS), continuation in looking for new polysaccharide-producing micro-organisms is promising. Marine bacteria, isolated from deep-sea hydrothermal vents, have demonstrated their ability to produce in aerobic conditions, unusual EPS. With the aim of discovering biological activities, EPS presenting different structural features were studied. An EPS secreted by Vibrio, diabolicus was evaluated on the restoration of bone integrity in experimental model and was demonstrated to be a strong bone-healing material. Another EPS produced by Alteromonas infernus was modified in order to obtain new... |
| Tipo: Text |
Palavras-chave: Hydrothermal vents; Exopolysaccharides; Bone healing; Biomimetic; Anticoagulant activity; Sources hydrothermales; Exopolysaccharide; Cicatrisation osseuse; Biomimétique; Activité anticoagulante. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-2117.pdf |
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| Camacho-chab, Juan Carlos; Guezennec, Jean; Chan-bacab, Manuel Jesus; Rios-leal, Elvira; Sinquin, Corinne; Muniz-salazar, Raquel; De La Rosa-garcia, Susana Del C.; Reyes-estebanez, Manuela; Ortega-morales, Benjamin Otto. |
| A previously reported bacterial bioemulsifier, here termed microbactan, was further analyzed to characterize its lipid component, molecular weight, ionic character and toxicity, along with its bioemulsifying potential for hydrophobic substrates at a range of temperatures, salinities and pH values. Analyses showed that microbactan is a high molecular weight (700 kDa), non-ionic molecule. Gas chromatography of the lipid fraction revealed the presence of palmitic, stearic, and oleic acids; thus microbactan may be considered a glycolipoprotein. Microbactan emulsified aromatic hydrocarbons and oils to various extents; the highest emulsification index was recorded against motor oil (96%). The stability of the microbactan-motor oil emulsion model reached its... |
| Tipo: Text |
Palavras-chave: Bioemulsifier; Emulsifying stability; Non-toxic; Microbacterium sp; Biotechnology. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00372/48356/48545.pdf |
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| Senni, Karim; Gueniche, Farida; Changotade, Sylvie; Septier, Dominique; Sinquin, Corinne; Ratiskol, Jacqueline; Lutomski, Didier; Godeau, Gaston; Guezennec, Jean; Colliec-jouault, Sylvia. |
| Biopolymers produced by marine organisms can offer useful tools for regenerative medicine. Particularly, HE800 exopolysaccharide (HE800 EPS) secreted by a deep-sea hydrothermal bacterium displays an interesting glycosaminoglycan-like feature resembling hyaluronan. Previous studies demonstrated its effectiveness to enhance in vivo bone regeneration and to support osteoblastic cell metabolism in culture. Thus, in order to assess the usefulness of this high-molecular weight polymer in tissue engineering and tissue repair, in vitro reconstructed connective tissues containing HE800 EPS were performed. We showed that this polysaccharide promotes both collagen structuring and extracellular matrix settle by dermal fibroblasts. Furthermore, from the native HE800... |
| Tipo: Text |
Palavras-chave: Marine hydrothermal bacteria; Glycosaminoglycan-mimetic; Collagen; Matrix metalloproteinases; Dermal fibroblast; Polysaccharides; Tissue engineering. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00138/24973/23072.pdf |
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| Gonthier, Isabelle; Rager, Marie-noëlle; Metzger, Pierre; Guezennec, Jean; Largeau, Claude. |
| The lipids of a deep-sea hydrothermal vent arch ae on, Thermococcus S 557, were isolated, purified and structurally determined. Based on acid methanolysis and spectroscopic studies, the polar lipids were shown to comprise diphytanyl glycerol and dibiphytanyl diglycerol, typical membrane lipids of Arch aea. From the neutral lipids, 2,3-di-O-dihydro-14,15-geranylgeranyl glycerol was isolated. This novel ether lipid is, very likely, a close intermediate in the biosynthesis of diphytanyl glycerol diether in Arch aea. |
| Tipo: Text |
Palavras-chave: Mass spectrometry; NMR; Novel glycerol diether lipid; Thermococcus sp; Archaea. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-736.pdf |
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| Colaco, Ana; Desbruyeres, Daniel; Guezennec, Jean. |
| The polar lipid fatty acid (PLFA) profiles of invertebrates living in chemosynthetic communities can indicate the degree to which these animals depend on specific types of bacteria. To identify the nutritional sources of various species from deep-sea hydrothermal vents of the Mid-Atlantic Ridge, a Principal Component Analysis was performed using individual PLFA profiles as descriptors. Two associations representing different feeding groups were identified: (i) mussels, commensal polychaetes and gastropods, (ii) shrimps and crabs. The first association relies more on sulphide-oxidizing bacteria, while the second one has more anaerobic sulphate-reducing bacteria biomarkers. Other small invertebrates reveal different diets. The polychaete Amathys lutzi shows... |
| Tipo: Text |
Palavras-chave: Mid Atlantic Ridge; Biomarkers; Hydrothermal vents; Fatty acids. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2538.pdf |
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| Guezennec, Jean; Rimbault, A; Godfroy, Anne; Fromage, M; Marec, F; Rocchiocioli, F. |
| The existence of deep-sea hydrothermal thermophilic archaebacteria raises interesting questions about their metabolism and metabolic products both in a natural environment and in a culture medium. Moreover, the use of these microorganisms as a potential source of molecules of biotechnological interest must be considered, in the light of the fact that metabolic produits can enhance the risk of microbially-induced corrosion. Organic acids formed by an anaerobic thermophilic sulphur-dependent archaebacterium were analysed as tert-butyldimethylsilyl derivatives by GC and GC/MS. Data indicated the presence in significant amounts of propanoic, 2-methyl propanoic, 3-(methylthio) propanoic, phenylacetic and 4-hydroxyphenylacetic acids. In addition, the use of... |
| Tipo: Text |
Palavras-chave: ARCHAEA; ORGANIC ACIDS; AMINO ACIDS; LABELED ISOTOPES. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00099/21011/18637.pdf |
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| Mancuso Nichols, Carol; Guezennec, Jean; Bowman, John. |
| Exopolysaccharides (EPSs) are high molecular weight carbohydrate polymers that make up a substantial component of the extracellular polymers surrounding most microbial cells in the marine environment. EPSs constitute a large fraction of the reduced carbon reservoir in the ocean and enhance the survival of marine bacteria by influencing the physicochemical environment around the bacterial cell. Microbial EPSs are abundant in the Antarctic marine environment, for example, in sea ice and ocean particles, where they may assist microbial communities to endure extremes of temperature, salinity, and nutrient availability. The microbial biodiversity of Antarctic ecosystems is relatively unexplored. Deep-sea hydrothermal vent environments are characterized by high... |
| Tipo: Text |
Palavras-chave: Ecosystems Hydrothermal Microbial; Polymers EPSs. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-624.pdf |
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| Dufourcq, R.; Chalkiadakis, Eletherios; Fauchon, M.; Deslandes, Eric; Kerjean, V.; Chanteau, S.; Petit, Elodie; Guezennec, Jean; Dupont-rouzeyrol, M.. |
| Marine bacteria are a rich source of bioactive metabolites. However, the microbial diversity of marine ecosystem still needs to be explored. The aim of this study was to isolate and characterize bacteria with antimicrobial activities from various marine coastal environment of New Caledonia. We obtained 493 marine isolates from various environments and samples of which 63 (12.8%) presented an antibacterial activity against a panel of reference pathogenic strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis). Ten out of the most promising strains were cultured, fractionated and screened for antibacterial activity. Four of them (NC282, NC412, NC272 and NC120) showed at least an activity against reference and... |
| Tipo: Text |
Palavras-chave: Antibacterial activity; Characterization; Marine bacteria; New Caledonia; Screening. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00174/28552/26994.pdf |
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| Guezennec, Jean. |
| In contrast to the situation of a few years ago, the phenomenon of microbiologically induced corrosion is now generally accepted as being one of a number of mechanisms whereby corrosion occurs. A considerable amount of multi-disciplinary effort has been expended to determine the extent of the problem and to understand the phenomenon. Microbial corrosion refers to the degradation of metallic or non metallic structures resulting from the presence and the activity of a variety of organisms on the surfaces. Although, in many cases, microbial corrosion is closely associated with biofouling phenomena, the area in which it causes most damages concern the deterioration of metallic structures in soils and sediments with the well-known sulphate-reducing bacteria. |
| Tipo: Text |
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| Ano: 1990 |
URL: https://archimer.ifremer.fr/doc/00479/59106/61743.pdf |
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| Guezennec, Jean; Antoine, Elisabeth; Conte, Max. |
| In marine environments cathodic protection using sacrificial anodes or impressed current is widely used. In aerated seawater a cathodic potential of – 800 mV/SCE is generally accepted as efficient against marine corrosion. Biofilms formed on the metallic surfaces exposed to seawater can promote localized corrosion and interfere with the cathodic polarization process. Experiments were conducted both in natural environments and with a monoculture of a marine bacterium in order to understand the relationship between cathodic protection and biofilm formation. Results indicated that, in the former case, there was no evidence that biofilms significantly affect the cathodic current demand. Conversely, in sterilized seawater inoculated with a single bacterial... |
| Tipo: Text |
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| Ano: 1992 |
URL: https://archimer.ifremer.fr/doc/00480/59137/61765.pdf |
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| Nichols, Carol Mancuso; Bowman, John; Guezennec, Jean. |
| A Gram-negative, aerobic, gliding, orange-yellow marine bacterium was isolated from particulate material sampled from the Southern Ocean. This strain produced an exopolysaccharide in liquid culture. 16S rRNA gene sequence analysis showed that this isolate was a member of the family Flavobacteriaceae, but represented a separate lineage. Major whole-cell fatty acids included i15:1 omega 10c, i15:0, beta-OH i15:0, a15:1 omega 10c, 15:0 and alpha-OH i15:0. The G+C content of the DNA was 49 mol%. Based on phylogenetic, phenotypic, chemotaxonomic and genotypic analyses, this bacterium was placed in a novel taxon as Olleya marilimosa gen. nov., sp. nov. with type strain CAM030(T) (=ACAM 1065(T)=CIP 108537(T)). |
| Tipo: Text |
Palavras-chave: Microbiology; Classification; Identification; Bacterie. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-457.pdf |
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| 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 |
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| Guezennec, Jean; Chalkadiahis, Elefterios; Lerat, Etienne; Loubersac, Lionel. |
| This text which deals with the potential of the marine bacteria articulates around six chapters. The first one offers general points of view on marine wealth. The second gives a typology of the various valuations of the living matter in the form of biotechnologies. The third specifies the meaning of the marine or blue biotechnologies and places the part occupied by bacteria. The fourth describes several ways fur valuating bacteria and their by products (biopolymers as EPS and PHA) and applications and offer a digression on medicine coming from the sea. The fifth chapter is interested in the atypical environments and the particular conditions they offer. The sixth is dedicated to the New-Caledonian case, its natural specificities and introduces the case of... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00414/52540/53353.pdf |
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| Petit, Anne-celine; Noiret, N; Sinquin, Corinne; Ratiskol, Jacqueline; Guezennec, Jean; Colliec-jouault, Sylvia. |
| Free-radical depolymerization with metallic catalysts has been investigated to depolymerize an exopolysaccharide (EPS), with a high molecular weight (> 10(6) g/Mol), produced by the bacterium Alteromonas macleodii subsp. fijiensis biovar deepsane. Three metals (copper, zinc and manganese) were used either alone or mixed. These metals led to the depolymerization of the high molecular weight bacterial polysaccharide with different efficiency. This study specifies some conditions required to produce, with good reproducibility and yield, EPS derivatives of reduced molecular weight ranging from 100,000 to 20,000 g/mol. The more influential parameters are specified. This is a first study to find suitable industrial conditions in the presence of these metallic... |
| Tipo: Text |
Palavras-chave: Bacterial exopolysaccharide; Free radical depolymerization; H202; Metal. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2146.pdf |
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| Nichols, Carol; Lardiere, Sandrine; Bowman, John; Nichols, Peter; Gibson, John; Guezennec, Jean. |
| Exopolysaccharides (EPS) may have an important role in the Antarctic marine environment, possibly acting as ligands for trace metal nutrients such as iron or providing cryoprotection for growth at low temperature and high salinity. Ten bacterial strains, isolated from Southern Ocean particulate material or from sea ice, were characterized. Whole cell fatty acid profiles and 16S rRNA gene sequences showed that the isolates included representatives of the genera Pseudoalteromonas, Shewanella, Polaribacter, and Flavobacterium as well as one strain, which constituted a new bacterial genus in the family Flavobacteriaceae. The isolates are, therefore, members of the "Gammaproteobacteria" and Cytophaga-Flexibacter-Bacteroides, the taxonomic groups that have been... |
| Tipo: Text |
Palavras-chave: Marine particulates; Sea ice; Marine bacteria; Antarctica; Exopolysaccharides. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-623.pdf |
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| Matou, Sabine; Colliec-jouault, Sylvia; Galy Fauroux, Isabelle; Ratiskol, Jacqueline; Sinquin, Corinne; Guezennec, Jean; Fischer, Anne-marie; Helley, Dominique. |
| The aim of this study was to determine the angiogenic properties of an oversulfated exopolysaccharide (OS-EPS) derived from a polysaccharide secreted by the mesophilic bacterium Alteromonas infernus. We compared the effect of this OS-EPS with that of a non-oversulfated exopolysaccharide (EPS) on human umbilical vein endothelial cell (HUVEC) proliferation, migration and differentiation induced by basic fibroblast growth factor (FGF-2) or vascular endothelial growth factor (VEGF). OS-EPS enhanced HUVEC proliferation by 58% when used alone, and by respectively 30% and 70% in the presence of FGF-2 and VEGF. OS-EPS also increased the density of tubular structures on Matrigel in the presence of FGF-2 or VEGF. Vascular tube fort-nation was related to alpha(6)... |
| Tipo: Text |
Palavras-chave: Matrigel; Collagen gel; Alpha 6 integrin subunit; Angiogenic growth factor; Polysaccharide; Angiogenesis. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-2118.pdf |
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| 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 |
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| 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 |
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| 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 |
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| Registros recuperados: 40 | |
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