Catherine Choquet

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Unilamellar liposomes were formed by controlled detergent dialysis of mixed micelles consisting of acetone-insoluble total polar lipids extracted from various methanogens and the detergent n-octyl-beta-D-glucopyranoside. The final liposome populations were studied by dynamic light scattering and electron microscopy. Unilamellar liposomes with mean diameters(More)
We consider the evolution of a reactive soluble substance introduced into the Poiseuille flow in a slit channel. The reactive transport happens in presence of dominant Péclet and Damköhler numbers. We suppose Péclet numbers corresponding to Taylor's dispersion regime. The two main results of the paper are the following. First, using the anisotropic(More)
In vitro protein synthesis in Vibrio costicola [poly(U)-directed incorporation of phenylalanine] was studied. The extent of protein synthesis was limited by the number of ribosomes present. Density gradient centrifugation experiments suggested that, after runoff of ribosomes from the artificial messenger, the 50S subunit was unable to attach to the(More)
Methanospirillum hungatei GP1 contained 50% of its ether core lipids (polar lipids less head groups) as tetraether lipids, and its plasma membrane failed to fracture along its hydrophobic domain during freeze-etching. The membrane of Methanosaeta ("Methanothrix") concilii did not contain tetraether lipids and easily fractured to reveal typical(More)
Methanococcus voltae cells were converted into protoplasts by suspension in anaerobic 0.1 M Tris-HCl buffer containing 0.4 M sucrose and 0.05 M NaCl as osmoprotectants. Protoplast formation was monitored microscopically by observing the conversion of the typical irregularly shaped (uneven peripheries) coccoid whole cells to rounded forms with smooth(More)
In vitro protein synthesis was studied in extracts of the moderate halophile Vibrio costicola by using as mRNAs the endogenous mRNA of V. costicola and the RNA of the R17 bacteriophage of Escherichia coli. Protein synthesis (amino acid incorporation) was dependent on the messenger, ribosomes, soluble cytoplasmic factors, energy source, and tRNA(FMet) (in(More)
Hydroxylated diether lipids are the most abundant lipids in Methanosarcina acetivorans, Methanosarcina thermophila, and Methanosarcina barkeri MS and Fusaro, regardless of the substrate used for growth. Structural analysis of the lipid moiety freed of polar head groups revealed that the hydroxydiether lipids of all the Methanosarcina strains were(More)
Usually the Stokes equations that govern a flow in a smooth thin domain (with thickness of order ε) are related to the Reynolds equation for the pressure p smooth. In this paper, we show that for a rough thin domain (with rugosities of order ε 2) the flow is governed by a modified Reynolds equation for a pressure p rough. Moreover we find the relation p(More)
A color processing procedure bases on the essential features of human perception of colors is presented. It allows the computation of colors in terms of the luminance, the hue and the saturation at every point of an image. Such color processing was used for segmentation and feature extraction of human bone marrow cell images acquired through successive red,(More)
Existence of weak solutions to a degenerate pseudo-parabolic equation modeling two-phase flow in porous media Abstract In this paper, we consider a degenerate pseudo-parabolic equation modeling two-phase flow in porous media, where dynamic effects in the difference of the phase pressures are included. Because of the special form of the capillary induced(More)