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| Bergeron, Jean-pierre. |
| A major spawning ground of the European anchovy (Engraulis encrasicolus) population in the Bay of Biscay is located near the mouth of the Gironde estuary. Variations in the river discharge affect the supply of nutrients to the coastal marine area encompassing anchovy spawning grounds. Two "Pegase" cruises (May-June 1997 and 1998) observed two contrasting situations: with and without a superficial layer of less saline water. Two new nutritional indices were used to assess potential effects (1) on carbohydrate assimilation rates by zooplankton estimated via pyruvate kinase (PK) activity measurements and (2) on nutritional condition of the anchovy larvae measured with the DNA/C index. Both indices indicated a much poorer situation in 1997 compared to 1998.... |
| Tipo: Text |
Palavras-chave: River outflow; Pyruvate kinase; DNA/C index; Bay of Biscay; Anchovy larvae. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-448.pdf |
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| Le Moullac, Gilles; Cheize, Marie; Gastineau, Olivier; Daniel, Jean-yves; Le Coz, Jean-rene; Huvet, Arnaud; Moal, Jeanne; Pouvreau, Stephane; Van Wormhoudt, A; Samain, Jean-francois. |
| The purpose of this study is to examine the response of the oyster Crassostrea gigas to sulphide at different biological scales. A first experiment was designed to measure for 20 h the clearance (CR) and oxygen consumption (OC) rates of oysters exposed at different concentrations of sulphide (0, 3, 6, 12, 20, and 40 mu M). The second experiment was carried out to evaluate the metabolic adaptations to chronic sulphide exposure for 10 days by measuring PK and PEPCK enzyme activities, succinate and alanine content, the adenylate energy charge (AEC), and the activity of the electron transport system (ETS)in whole oysters at above 20 mu M. PK and PEPCK mRNAs and enzyme activities have been measured in adductor muscle. When exposed to sulphide above 20 mu M, CR... |
| Tipo: Text |
Palavras-chave: ATP; AEC; Electron transport system; Succcinate; Alanine; Phosphoenolpyruvate carboxykinase; Pyruvate kinase; Oxygen consumption; Clearance rate; Crassostrea gigas; Sulphide; Oyster. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3924.pdf |
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| Le Moullac, Gilles; Queau, Isabelle; Le Souchu, Pierrick; Pouvreau, Stephane; Moal, Jeanne; Le Coz, Jean-rene; Samain, Jean-francois. |
| The purpose of this study was to examine the responses of the oyster C. gigas to oxygen levels at subcellular and whole-organism levels. Two experiments were carried out. The first experiment was designed to measure at 15°C, 20°C and 25°C for 20 hours the clearance (CR) and oxygen consumption (OC) rates of oysters exposed at different concentrations of oxygen. The goal of this first part was to estimate the hypoxic threshold for oysters below which their metabolism shifts toward anaerobiosis, by estimating the oxygen critical point (PcO2) at 15, 20 and 25°C. The second experiment was carried out to evaluate the metabolic adaptations to hypoxia for 20 days at three temperatures: 12°C, 15°C and 20°C. The metabolic pathways were characterized by the... |
| Tipo: Text |
Palavras-chave: Succinate; Alanine; Phosphoenolpyruvate carboxykinase; Pyruvate kinase; Temperature; Hypoxia; Oysters. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2693.pdf |
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| Bergeron, Jean-pierre. |
| The study examines the spatial variations over the French continental shelf of the southern Bay of Biscay (North-East Atlantic) in the nutritional condition of anchovy (Engraulis encrasicolus L.) larvae which was estimated through their DNA/C index. The same cruise yielded quantitative estimates of two metabolic descriptors of the functioning of mesozooplanktonic communities, the enzymes pyruvate kinase (PK) and trypsin, for the first time evaluated simultaneously. The aim was to appraise quality and quantity of matter assimilated by the mesozooplankton and to specify whether the main components of prey ingested by copepods are principally carbohydrates, through PK activity, or protein, under the action of the digestive endopeptidase trypsin. The larval... |
| Tipo: Text |
Palavras-chave: Anchovy larvae; Bay of Biscay; DNA/C index; Mesozooplankton; Pyruvate kinase; Trypsin. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6473.pdf |
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| Panserat, Stéphane; Plagnes Juan, E; Kaushik, Sadasivam. |
| Rainbow trout (Oncorhynchus mykiss) are known to use dietary carbohydrates poorly. One of the hypotheses to explain the poor utilisation of dietary glucose by these fish is a dysfunction in nutritional regulation of hepatic glucose metabolism. In this study, we obtained partial clones of rainbow trout cDNAs coding for a glucose transporter (Glut2), and for the enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (6PF-2K/F-2,6BPase), fructose-1,6-bisphosphatase (FBPase) and pyruvate kinase (PI(), Their deduced amino acid sequences were highly similar to those of mammals (up to 80% similarity), In a study of nutritional regulation, the Glut2 gene was highly expressed in the liver irrespective of the nutritional status of the trout, in agreement with... |
| Tipo: Text |
Palavras-chave: Oncorhynchus mykiss; Trout; Bifunctional enzyme; Pyruvate kinase; Fructose bisphosphatase; Glucose transporter; Glucose metabolism; Liver metabolism. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-415.pdf |
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| Bergeron, Jean-pierre; Herbland, Alain. |
| Estimates of carbohydrate assimilation within the mesozooplankton compartment are a fundamental concern in oceanography because they give a general expression of the biologically-regulated incorporation of metabolic fuel produced from inorganic nutrients by phytoplankton in the sea. A new tool is proposed for the assessment of such processes. It is based on the measurement of the activity of an enzyme, pyruvate kinase (PK), on samples of the whole mesozooplankton community. Here, the results are presented of an early attempt at such an implementation in the Bay of Biscay (north-east Atlantic) in springtime. A main area situated in front of an estuary (Gironde) has been extensively studied-the same sampling grid was covered on three occasions (two 20 day... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Zooplankton; Phytoplankton; Pyruvate kinase; Carbohydrate. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-452.pdf |
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