References of "Libioulle, Cécile"
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See detailNovel Crohn disease locus identified by genome-wide association maps to a gene desert on 5p13.1 and modulates expression of PTGER4.
Libioulle, Cécile ULg; Louis, Edouard ULg; Hansoul, Sarah ULg et al

in PLoS Genetics (2007), 3(4), 538-543

To identify novel susceptibility loci for Crohn disease (CD), we undertook a genome-wide association study with more than 300,000 SNPs characterized in 547 patients and 928 controls. We found three ... [more ▼]

To identify novel susceptibility loci for Crohn disease (CD), we undertook a genome-wide association study with more than 300,000 SNPs characterized in 547 patients and 928 controls. We found three chromosome regions that provided evidence of disease association with p-values between 10(-6) and 10(-9). Two of these (IL23R on Chromosome 1 and CARD15 on Chromosome 16) correspond to genes previously reported to be associated with CD. In addition, a 250-kb region of Chromosome 5p13.1 was found to contain multiple markers with strongly suggestive evidence of disease association (including four markers with p < 10(-7)). We replicated the results for 5p13.1 by studying 1,266 additional CD patients, 559 additional controls, and 428 trios. Significant evidence of association (p < 4 x 10(-4)) was found in case/control comparisons with the replication data, while associated alleles were over-transmitted to affected offspring (p < 0.05), thus confirming that the 5p13.1 locus contributes to CD susceptibility. The CD-associated 250-kb region was saturated with 111 SNP markers. Haplotype analysis supports a complex locus architecture with multiple variants contributing to disease susceptibility. The novel 5p13.1 CD locus is contained within a 1.25-Mb gene desert. We present evidence that disease-associated alleles correlate with quantitative expression levels of the prostaglandin receptor EP4, PTGER4, the gene that resides closest to the associated region. Our results identify a major new susceptibility locus for CD, and suggest that genetic variants associated with disease risk at this locus could modulate cis-acting regulatory elements of PTGER4. [less ▲]

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See detailChanges in major intracellular osmolytes in L-929 cells following rapid and slow application of hyperosmotic media.
Libioulle, Cécile ULg; Corbesier, L.; Gilles, Raymond ULg

in Comparative Biochemistry & Physiology Part A : Molecular & Integrative Physiology (2001), 130(3), 461-70

Cultured L-929 cells respond to media-made hyperosmotic (600 mOsmol/kg H2O) by addition of NaCl, sorbitol or proline by adjusting successively their intracellular level in different osmolytes: Na+, K ... [more ▼]

Cultured L-929 cells respond to media-made hyperosmotic (600 mOsmol/kg H2O) by addition of NaCl, sorbitol or proline by adjusting successively their intracellular level in different osmolytes: Na+, K+, amino acids and sorbitol. In the NaCl medium, Na+ and K+ are first to increase. Their concentration is then down-regulated while they are replaced by less disrupting osmolytes: amino acids and sorbitol. The amino-acid level is also adjusted with respect to the increase in sorbitol which starts only after 24 h, depending on the induction of aldose reductase. A similar evolution in the amount of these osmolytes is observed, with different time scales and amplitudes, depending on whether the osmotic shocks are applied abruptly or slowly, in a more physiological way. The interplay between the osmolytes is also different depending on their availability in the external medium. Such complex evolutions indicate that a cascade of interacting signals must be considered to account for the overall regulation process. It can hardly be fitted into a model implicating a single primary signalling event (early increase in ions or decrease in cell volume) as usually postulated. Also, the volume up-regulation is not significantly different in the different conditions, showing that it is not primarily dependent on the adjustment of the intracellular osmolarity which is reached immediately upon cell shrinkage and is maintained all over, independently of the availability and changes in nature of the osmolytes. [less ▲]

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See detailMolecular adaptations of alpha-amylase from psychrophilic bacteria
Feller, Georges ULg; LIBIOULLE, Cécile ULg; Payan, Françoise et al

Poster (1995)

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See detailEffect of high osmolarity acclimation on tolerance to hyperosmotic shocks in L929 cultured cells.
Gilles, Raymond ULg; Belkhir, M.; Compère, Philippe ULg et al

in Tissue & Cell (1995), 27(6), 679-687

Application of abrupt, large hyperosmotic shocks induces in L929 cultured cells changes similar to those previously described in other cell types, notably a hypercondensation of the nuclear chromatin ... [more ▼]

Application of abrupt, large hyperosmotic shocks induces in L929 cultured cells changes similar to those previously described in other cell types, notably a hypercondensation of the nuclear chromatin. This paper shows that; 1) this phenomenon is concomitant with a complete disappearance of deoxyribonucleic acid, as visualized by immunogold labelling, from the nucleoplasmic spaces; 2) acclimation to high osmolarities (600 mOsm) by addition to the culture medium of NaCl, sorbitol or proline protects the cells from these effects, which appear to be largely attenuated-acclimated cells also survive much better to the osmotic shock than do control cells and; 3) the best protection seems to be provided by sorbitol and NaCl. Proline acclimation is less effective. These effects are discussed in terms of increased tolerance to NaCl load induced at the level of different macromolecules by so-called 'compensatory' organic compounds. [less ▲]

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See detailMolecular adaptations of alpha-amylase from psychrophilic bacteria.
Feller, Georges ULg; LIBIOULLE, Cécile ULg; Payan, Françoise et al

Poster (1994)

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See detailMolecular adaptations of alpha-amylase from psychrophilic bacteria
Feller, Georges ULg; LIBIOULLE, Cécile ULg; Payan, Françoise et al

Poster (1994)

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See detailMolecular adaptations of alpha-amylase from psychrophilic bacteria
Feller, Georges ULg; LIBIOULLE, Cécile ULg; Payan, Françoise et al

Poster (1994)

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See detailPurification, Characterization, and Nucleotide Sequence of the Thermolabile Alpha-Amylase from the Antarctic Psychrotroph Alteromonas Haloplanctis A23
Feller, Georges ULg; Lonhienne, T.; Deroanne, Christophe ULg et al

in Journal of Biological Chemistry (1992), 267(8), 5217-21

The alpha-amylase excreted by the antarctic bacterium Alteromonas haloplanctis was purified and the corresponding amy gene was cloned and sequenced. N- and C-terminal amino acid sequencing were used to ... [more ▼]

The alpha-amylase excreted by the antarctic bacterium Alteromonas haloplanctis was purified and the corresponding amy gene was cloned and sequenced. N- and C-terminal amino acid sequencing were used to establish the primary structure of the mature A. haloplanctis alpha-amylase which is composed of 453 amino acids with a predicted Mr of 49,340 and a pI of 5.5. Three Ca2+ ions are bound per molecule and its activity is modulated by chloride ions. Within the four consensus sequences, Asp-174, Glu-200, and Asp-264 are the proposed catalytic residues. The psychrotrophic A. haloplanctis alpha-amylase is characterized by a high amylolytic activity at low temperatures, a reduced apparent optimal temperature, and typical thermodynamic activation parameters A. haloplanctis alpha-amylase has also a low thermal stability as demonstrated by the temperature effect on both activity and secondary structure. It is suggested that structure flexibility and lower sensitivity of secondary structure to temperature variations in the low temperature range are the main structural adaptations of the psychrotrophic enzyme. The unusual stacking of small amino acids around the catalytic residues is proposed as a factor inducing active site flexibility and concomitant high activity of the enzyme at low temperatures. [less ▲]

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