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| Registros recuperados: 19 | |
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| Leroy, Celine; Compere, Chantal; Delbarre Ladrat, Christine; Raguenes, Gerard; Ghillebaert, François; Combes, Didier. |
| Une nouvelle bactérie marine du genre Pseudoalteromonas sp., D41, formant rapidement des biofilms sur tout type de matériau (verre, acier inoxydable, Téflon) a été isolée en Baie de Brest. L’objectif de ce présent travail est de caractériser et décrire cette bactérie capable de produire des exopolymères constitués en majorité de protéines. Le rôle des protéines sécrétées, dans les mécanismes d’adhésion, est discuté. |
| Tipo: Text |
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| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00088/19950/17617.pdf |
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| Rigouin, Coraline; Delbarre Ladrat, Christine; Sinquin, Corinne; Colliec-jouault, Sylvia; Dion, M. |
| To find biocatalyst allowing depolymerization of new polysaccharides, one needs to get a sensitive and well adapted method to a screening program. This led us to compare biochemical methods of detection of the depolymerization. Currently used methods such as reducing sugars assays, double bond monitoring or molecular weight determination were tested to follow the kinetic of depolymerization with different enzyme / polysaccharide couples. The range of concentrations of assorted enzymes allowed us to identify the most sensitive and appropriate method to detect polysaccharide degradation. Reducing sugars assays are quantitative, sensitive and almost usable with all kind of polysaccharide but some compounds may interfere with them. When polysaccharide is... |
| Tipo: Text |
Palavras-chave: Detection; Enzyme; Depolymerization; Carbohydrate. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4723.pdf |
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| Cheret, Romuald; Delbarre Ladrat, Christine; De Lamballerie Anton, Marie; Verrez-bagnis, Veronique. |
| Post mortem tenderization is one of the most unfavourable quality changes in fish muscle and this contrasts with muscle of mammalian meats. The tenderization can be partly attributed to the acid lysosomal cathepsins and cytosolic neutral calcium-activated calpains. In this study, these proteases from fish and bovine muscles were quantified and compared. The cathepsin B and L activities were in more important amounts in sea bass white muscle than in bovine muscle. On the other hand, cathepsin D activity was 1.4 times higher in meat that in fish muscle, while cathepsin H was negligible in both muscles. Calpain activities were similar in both types of muscle. Moreover, calpastatin (calpain endogenous inhibitor) level is 3.9 times higher in sea bass white... |
| Tipo: Text |
Palavras-chave: Meat; Fish; Protease; Cathepsin; Calpain. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3646.pdf |
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| Passerini, Delphine; Fecamp, Florian; Marchand, Laetitia; Kolypczuk, Laetitia; Bonnetot, Sandrine; Sinquin, Corinne; Verrez-bagnis, Veronique; Hervio Heath, Dominique; Colliec Jouault, Sylvia; Delbarre Ladrat, Christine. |
| In the marine environment, biofilm formation is an important lifestyle for microorganisms. A biofilm is comprised of cells embedded in an extracellular matrix that holds them close together and keeps the biofilm attached to the colonized surface. This predominant lifestyle and its main regulation pathway, namely quorum-sensing (QS), have been shown to induce specific bioactive metabolites. In this study, we investigated the biofilm formation by two marine bacteria belonging to the Vibrio species to discover potentially innovative bioactive compounds. We proposed a protocol to isolate biofilm extracts, to analyze their biochemical composition, and to compare them to planktonic cell extracts. Cells were grown attached to a plastic surface; extracts were... |
| Tipo: Text |
Palavras-chave: Vibrio; Biofilm; Polysaccharide; Quorum-sensing; Activity. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00592/70381/68461.pdf |
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| Akoumany, Katy; Zykwinska, Agata; Sinquin, Corinne; Marchand, Laetitia; Fanuel, Mathieu; Ropartz, David; Rogniaux, Hélène; Pipelier, Muriel; Delbarre Ladrat, Christine; Colliec Jouault, Sylvia. |
| Bacteria from deep-sea hydrothermal vents constitute an attractive source of bioactive molecules. In particular, exopolysaccharides (EPS) produced by these bacteria become a renewable source of both biocompatible and biodegradable molecules. The low molecular weight (LMW) derivatives of the GY785 EPS produced by the deep-sea hydrothermal vent strain Alteromonas infernus have previously displayed some biological properties, similar to those of glycosaminoglycans (GAG), explored in cancer and tissue engineering. These GAG-mimetic derivatives are obtained through a free radical depolymerization process, which could, however, affect their structural integrity. In a previous study, we have shown that A. infernus produces depolymerizing enzymes active on its own... |
| Tipo: Text |
Palavras-chave: Deep-sea bacterium; Alteromonas infernus; Wild-type strain; Exopolysaccharides; Glycosaminoglycan-mimetic; Enzymatic depolymerization; Structural analysis; Mass spectrometry. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00515/62644/67021.pdf |
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| Cheret, Romuald; Delbarre Ladrat, Christine; Verrez-bagnis, Veronique; De Lamballerie, Marie. |
| Calpains (calcium-activated neutral proteases) of sea bass (Dicentrarchus labrax L.) muscle may participate in the degradation of muscle tissue during postmortem storage. These enzymes are regulated by calpastatin, their endogenous specific inhibitor. The objective of this study was to evaluate the changes encountered by the calpain system during the postmortem storage of fish muscle after high-pressure treatment. From 100 MPa, high-pressure treatment of purified calpains results in a loss of their activity as well as in the dissociation of the heterodimeric form. In muscle, the high-pressure processing decreases the initial activity of calpain. This loss in activity may be due to an inactivation by a change of structure. Initial calpastatin activity is... |
| Tipo: Text |
Palavras-chave: Postmortem denaturation; High pressure; Fish; Calpain system. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2786.pdf |
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| Leroy, C.; Delbarre Ladrat, Christine; Ghillebaert, F.; Compere, Chantal; Combes, D.. |
| The antifouling potential of commercial hydrolases, four proteases, seven glycosidases and one lipase was evaluated on the adhesion of marine Pseudoalteromonas sp. D41. The experimental method, adapted to screen antifouling agents, was based on bacterial adhesion in natural sterile sea water in a microtiter plate and on total biomass quantification by the fluorescent dye DAPI (4[prime]6-diamidino-2-phenylindole). Savinase (subtilisin) was the most effective hydrolase in both the prevention of bacterial adhesion and the removal of adhered bacteria. However, some enzymatic preparations tested such as Amano protease were not only ineffective but also increased the number of adhered bacterial cells. Enumeration using epifluorescence microscopy of CTC... |
| Tipo: Text |
Palavras-chave: Marine biofilm; Antifouling; Pseudoalteromonas; Enzymes; Adhesion. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6140.pdf |
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| Cheret, Romuald; Chapleau, Nicolas; Delbarre Ladrat, Christine; Verrez-bagnis, Veronique; De Lamballerie, Marie. |
| High pressure is an innovative non-thermal food-preservation technology. We studied the effect of high-pressure treatment up-to 500 MPa for 5 min on physical characteristics of sea bass fillets after 0, 7, and 14 d of refrigerated storage.. Color results exhibited an increase of lightness and a slight change of hue, which might be imperceptible in cooked fish. High-pressure treatment induced a decrease of exudation and water-holding capacity Pressure treatment above 300 MPa provoked higher fish hardness after storage than in untreated sample, proving the ability of high pressure to improve textural, quality of chilled, stored fish fillet. These assessments were corroborated with microstructure observations. We showed that high-pressure treatment at 500 MPa... |
| Tipo: Text |
Palavras-chave: Preservation; Microstructure; Texture profile analysis; High pressure; Fish. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-734.pdf |
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| Verrez-bagnis, Veronique; Soree, Marion; Passerini, Delphine; Kolypczuk, Laetitia; Marchand, Laetitia; Bonnetot, Sandrine; Fecamp, Florian; Lozach, Solen; Hervio Heath, Dominique; Delbarre Ladrat, Christine. |
| Vibrio spp. are ubiquitous marine bacteria that are ecologically and metabolically diverse members of planktonic and animal associated microbial communities. They encompass the ancient and well-studied human pathogen, Vibrio cholerae, and two other human pathogens, V. vulnificus and V. parahaemolyticus, as well as some less thoroughly characterized animal pathogens. Virulence is based on a wide diversity of mechanisms involved in motility and host colonization, in ability to persist and develop, and in damage generation. Polysaccharides may play major roles in virulence and are major components of extracellular polymeric matrix synthesized upon biofilm growth. They may also exhibit biological features, especially those similar to animal-derived... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00514/62605/66965.pdf |
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| Cheret, Romuald; Hernandez Andres, Aránzazu; Delbarre Ladrat, Christine; De Lamballerie, Marie; Verrez-bagnis, Veronique. |
| Contrary to other preservation methods like thermal treatments, high pressure can destroy microorganisms without affecting the nutritional quality, color, or food texture. The firm texture of fish flesh is an important quality parameter. During the refrigerated storage, the tissue becomes softer and the muscle is deteriorated by different proteases. The aim of this study was to study the modification of the fish muscle proteins after high-pressure treatment during the refrigerated storage and to evaluate the effect of high-pressure treatment level on the post-mortem protein changes and enzyme activities. The calpain activity decreased with the high-pressure treatment and evolved differently during the refrigerated storage, depending on the level of... |
| Tipo: Text |
Palavras-chave: Cathepsins; Calpains; Sarcoplasmic proteins; Myofibrillar proteins; Post mortem denaturation; High pressure; Fish. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1708.pdf |
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| Delbarre Ladrat, Christine; Verrez-bagnis, Veronique; Noel, Joelle; Fleurence, Joel. |
| The effects of a milli(m)-calpain isolated from the white muscle of sea bass (Dicentrarchus labrax L) and commercial cathepsins B, D and L, used in combination on the myofibrillar and sarcoplasmic proteins were examined. Protein digestion was first performed by the endogenous m-calpain, (luring 2 h before the addition of a mixture of cathepsins B, D and L and a further incubation up to 22 h. Calpain degraded a 27 kDa sarcoplasmic component as well as myosin heavy chain, a-actinin, desmin and a 32 kDa component from the myofibrillar fraction. A 97 kDa component and the assumed creatine kinase-aldolase doublet were degraded during the incubation of sarcoplasmic proteins with the cathepsin mixture while, among the myofibrillar proteins, myosin, actin,... |
| Tipo: Text |
Palavras-chave: Postmortem aging; Fish muscle; Proteolysis; Cathepsins; Neutral calcium dependent protease. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-1682.pdf |
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| Delbarre Ladrat, Christine; Cheret, Romuald; Taylor, Romuald; Verrez-bagnis, Veronique. |
| Introduction : Quality attributes of fish flesh, including food safety, organoleptic features, nutritional quality and aptitude to industrial transformation, influence consumption and acceptability of fish as food. Fish sensorial changes and texture properties are closely linked to freshness. Along with ante mortem muscle biochemistry, postmortem biochemical processes are directly linked to final quality attributes. The understanding of postmortem mechanisms is a prerequisite for an accurate control of the quality of commercialized fish by the identification of objective markers or indicators. Postmortem tenderization is one of the most important quality attributes of fish muscle. Loss of freshness is due to a complex combination of biochemical, chemical... |
| Tipo: Text |
Palavras-chave: Indicator; Quality; Proteolysis; Postmortem; Fish muscle. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1810.pdf |
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| Registros recuperados: 19 | |
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