Frédéric Dubois

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The roles of two cytosolic maize glutamine synthetase isoenzymes (GS1), products of the Gln1-3 and Gln1-4 genes, were investigated by examining the impact of knockout mutations on kernel yield. In the gln1-3 and gln1-4 single mutants and the gln1-3 gln1-4 double mutant, GS mRNA expression was impaired, resulting in reduced GS1 protein and activity. The(More)
A new computer haptics algorithm to be used in general interactive manipulations of deformable virtual objects is presented. In multimodal interactive simulations, haptic feedback computation often comes from contact forces. Subsequently, the fidelity of haptic rendering depends significantly on contact space modeling. Contact and friction laws between(More)
A retrospective survey of 7 European centers involving 20 surgeons who undertook 1,236 laparoscopic cholecystectomies was performed. The procedure was completed in 1,191 patients. Conversion to open cholecystectomy was necessary in 45 patients (3.6%) either because of technical difficulty (n = 33), the onset of complications (n = 11), or instrument failure(More)
To better understand the genetic variability for nitrogen use efficiency in winter wheat is a necessity in the frame of the present economic and ecological context. The objective of this work was to investigate the role of the enzymes glutamine synthetase (GS) and glutamate dehydrogenase (GDH), and other nitrogen (N)-related physiological traits in the(More)
 Glutamine synthetase (GS) catalyses the formation of glutamine (a major form of nitrogen transport in plants) in an ATP-dependent reaction using ammonium and glutamate. This enzyme is present in the plastids and/or in the cytosol depending on the plant or the organ examined. In order to understand the role of GS isoforms in the remobilization of leaf(More)
A novel Arabidopsis thaliana mutant, named hoc, was found to have an high organogenic capacity for shoot regeneration. The HOC locus may be involved in cytokinin metabolism leading to cytokinin-overproduction. In vitro, hoc root explants develop many shoots in the absence of exogenous growth regulators. The mutant displays a bushy phenotype with(More)
We present the first cloning and study of glutamine synthetase (GS) genes in wheat (Triticum aestivum L.). Based on sequence analysis, phylogenetic studies and mapping data, ten GS sequences were classified into four sub-families: GS2 (a, b and c), GS1 (a, b and c), GSr (1 and 2) and GSe (1 and 2). Phylogenetic analysis showed that the wheat GS sub-families(More)
Serologic markers of hepatitis B virus (HBV), including HBV DNA, and of hepatitis delta virus were measured in three villages in Gabon. Of 303 subjects studied, 19% were carriers of hepatitis B surface antigen (HBsAg); 8.5% of these had anti-delta antibodies. No difference among the three villages was observed. All HBV DNA carriers were children less than(More)
We assessed prognostic factors in 115 patients with serologically defined fulminant hepatitis B. The diagnosis in each case was based on the finding of IgM antibody to the hepatitis B core antigen in serum. Multivariate analysis showed that factor V level (p less than 0.001), patient's age (p = 0.001), absence of detectable HBsAg by radioimmunoassay (p =(More)
The subcellular localization of glutamine synthetase in tobacco and the differential expression of two genes encoding cytosolic enzyme was investigated using both immunocytochemistry and in situ hybridization. Two full length cDNA clones each encoding cytosolic GS (Glnl-3 and Glnl-5) were isolated from a tobacco seedling cDNA library. A strong homology was(More)