Consulta: creatorFacets:"Bacca, Helene"
Registros recuperados: 4
Data/hora: 03/06/2024 11:13:08

Etude des voies metaboliques des sucres chez l'huitre creuse crassostrea gigas. Implication dans les mortalites estivales.
Provedor de dados: 5
Autores: Bacca, Helene.
Glycogen, the main form of glucose reserve in bivalves, is known to play a key energetic role in the Pacific oyster (Crassostrea gigas) annual reproduction cycle. The aim of this work was to study the pathways of glycogen synthesis and utilization in order to explain the relationships between energy, reproduction and oyster summer mortality events. We first characterized full length mRNA sequences of Glycogen synthase (Cg-GYS) and Glycogen phosphorylase (Cg-GPH). Biochemical determination of enzymatic activities and adjustment of a RNA absolute quantification method allowed us to study several regulation levels for both markers. Quantities of Cg-GYS and Cg-GPH mRNAs showed seasonal variations, with opposite maximum periods, corresponding to glycogen...
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/these-3333.pdf

Genetically based resistance to summer mortality in the Pacific oyster (Crassostrea gigas) and its relationship with physiological, immunological characteristics and infection processes
Provedor de dados: 5
Autores: Samain, Jean-francois; Degremont, Lionel; Soletchnik, Patrick; Haure, Joel; Bedier, Edouard; Ropert, Michel; Moal, Jeanne; Huvet, Arnaud; Bacca, Helene; Van Wormhoudt, A; Delaporte, Maryse; Costil, K; Pouvreau, Stephane; Lambert, Christian; Boulo, Viviane; Soudant, Philippe; Nicolas, Jean-louis; Leroux, Frederique; Renault, Tristan; Gagnaire, Beatrice; Geret, Florence; Boutet, Isabelle; Burgeot, Thierry; Boudry, Pierre.
Summer mortality of Pacific oysters is known in several countries. However no specific pathogen has been systematically associated with this phenomenon. A complex combination of environmental and biological parameters has been suggested as the cause and is now starting to be identified. A high genetic basis was found for survival in oysters when a first generation (G1) was tested in three sites during summer. This paper presents a synthesis on physiological characteristics of two selected groups ('R' and 'S', from families selected for resistance and susceptibility to summer mortality respectively), of the second and third generations. R and S showed improvement or reduction of survival compared with the control in both field and laboratory trials...
Tipo: Text
Palavras-chave: ROS; Temperature; Stress; Hemocytes; Reproduction; Genetic selection; Resistant oyster; Crassostrea gigas; Pacific Oyster; Summer mortality.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2809.pdf

Transcriptional regulation of pyruvate kinase and phosphoenolpyruvate carboxykinase in the adductor muscle of the oyster Crassostrea gigas during prolonged hypoxia
Provedor de dados: 5
Autores: Le Moullac, Gilles; Bacca, Helene; Huvet, Arnaud; Moal, Jeanne; Pouvreau, Stephane; Van Wormhoudt, A.
The response of Crassostrea gigas to prolonged hypoxia was investigated for the first time by analyzing the metabolic branch point formed by pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK). PK and PEPCK cDNAs were cloned and sequenced. The main functional domains of the PK sequence, such as the binding sites for ADP/ATP and phosphoenolpyruvate (PEP), were identified whereas the PEPCK sequence showed the specific domain to bind PEP in addition to the kinase-1 and kinase-2 motifs to bind guanosine triphosphate (GTP) and Mg2+, specific for all PEPCKs. A C-terminal extension was detected for the first time in eukaryota PK. Separation of mitochondrial and cytosolic fraction showed that more than 92% of the PEPCK enzyme activity was cytosolic...
Tipo: Text
Palavras-chave: Succinate alanine carboxykinase phosphoenolpyruvate pyruvate kinase hypoxia Oyster.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2683.pdf

Molecular cloning and seasonal expression of oyster glycogen phosphorylase and glycogen synthase genes
Provedor de dados: 5
Autores: Bacca, Helene; Huvet, Arnaud; Fabioux, Caroline; Daniel, Jean-yves; Delaporte, Maryse; Pouvreau, Stephane; Van Wormhoudt, A; Moal, Jeanne.
To investigate the control at the mRNA level of glycogen metabolism in the cupped oyster Crassostrea gigas, we report in the present paper the cloning and characterization of glycogen phosphorylase and synthase cDNAs (Cg-GPH and Cg-GYS, respectively, transcripts of main enzymes for glycogen use and storage), and their first expression profiles depending on oyster tissues and seasons. A strong expression of both genes was observed in the labial palps and the gonad in accordance with specific cells located in both tissues and ability to store glucose. Cg-GPH expression was also found mainly in muscle suggesting ability to use glycogen as readily available glucose to. supply its activity. For seasonal examinations, expression of Cg-GYS and Cg-GPH genes...
Tipo: Text
Palavras-chave: Reproduction; Regulation; Oyster; Glycogen; Expression; Gene; Energy; Crassostrea gigas; Bivalve.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-435.pdf