References of "Libioulle, Cécile"
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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 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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