Hélène Thérisod

Université de La Rochelle, La Rochelle, Poitou-Charentes, France

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Publications (13)30.91 Total impact

  • H. THERISOD · Y. LETOURNEUX · M. THERISOD
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 05/2010; 29(21). DOI:10.1002/chin.199821202
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    ABSTRACT: The O-chain polysaccharide (O-PS) of Bordetella avium was isolated from the lipopolysaccharide by mild acid hydrolysis to remove the lipid A, followed by hydrofluorolysis to remove the lipopolysaccharide core oligosaccharide leaving a residual O-PS for structural analysis. High resolution 1H and 13C NMR and MALDI studies showed the O-chain to be a polymer composed of 1,4-linked 2-acetamidino-3-[3-hydroxybutanamido]-2,3-dideoxy-β-D- glucopyranosyluronic acid residues. © 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.
    FEBS Letters 02/2003; 535(1-3):11-6. DOI:10.1016/S0014-5793(02)03843-7 · 3.34 Impact Factor
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    ABSTRACT: The O-chain polysaccharide (O-PS) of Bordetella avium was isolated from the lipopolysaccharide by mild acid hydrolysis to remove the lipid A, followed by hydrofluorolysis to remove the lipopolysaccharide core oligosaccharide leaving a residual O-PS for structural analysis. High resolution 1H and 13C NMR and MALDI studies showed the O-chain to be a polymer composed of 1,4-linked 2-acetamidino-3-[3-hydroxybutanamido]-2,3-dideoxy-β-D-glucopyranosyluronic acid residues.
  • H Therisod · D Karibian · M.B Perry · M Caroff
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    ABSTRACT: The Yersinia genus includes human and animal pathogens (plague, enterocolitis) as well as non-pathogens. The lipopolysaccharide of the facultative pathogen Yersinia pseudotuberculosis has been implicated in the invasiveness of these bacteria. In this work, we have investigated the fine structure of the lipid A isolated from Y. pseudotuberculosis lipopolysaccharide using chemical analyses, gas chromatography/mass spectrometry, plasma desorption mass spectrometry, and matrix-assisted laser desorption mass spectrometry. Arabinose (Ara) and aminoarabinose (Ara-4N) esterified the phosphates as in Yersinia pestis lipid A. The acylation of Y. pseudotuberculosis lipid A differed from those found in Yersinia enterocolitica, Yersinia ruckeri, and Y. pestis lipopolysaccharides (LPSs): in the distribution of fatty acids between the two glucosamines in the fully acylated hexaacyl molecular species and by the acyloxyacyl substitution at position C-2′, where the Y. pseudotuberculosis lipid A has a C14OC16 making it closest to that of Y. pestis.
    International Journal of Mass Spectrometry 09/2002; 219(3):549-557. DOI:10.1016/S1387-3806(02)00706-6 · 2.23 Impact Factor
  • Hélène Therisod · Valérie Labas · Martine Caroff
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    ABSTRACT: A rapid method for the microscale extraction of lipopolysaccharides (endotoxins, LPSs) from rough-type Gram-negative bacteria was developed using thin-layer chromatography (TLC) combined with improved conditions for LPS analysis by mass spectrometry. TLC of intact bacteria on silica gel plates in an appropriate solvent selectively extracted and separated their LPS components. The bands of molecular species were scraped from the plates after nondestructive visualization, directly mixed with matrix, and analyzed by laser desorption time-of-flight mass spectrometry. Lipids A and Re-type LPSs were analyzed after transfer to a membrane. Adding citric acid to the matrix gave greatly improved mass spectra. The system allows characterization of bacterial LPS at the microscale level and is equally well applicable to heterogeneous LPS and lipid A preparations (Escherichia coli lipid A and Bordetella lipopolysaccharides were used). The technique provides a rapid determination of the heterogeneity of unmodified preparations and the determination of the molecular weight of each separated component.
    Analytical Chemistry 09/2001; 73(16):3804-7. DOI:10.1021/ac010313s · 5.83 Impact Factor
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    Hélène Thérisod · Mario A Monteiro · Malcolm B Perry · Martine Caroff
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    ABSTRACT: The lipid A structure of the Gram-negative bacterium Helicobacter mustelae, a ferret gastric pathogen responsible for the onset of gastric diseases in its host, was investigated. Two variant lipid A structures were found in the same strain. One structure contained a bisphosphorylated beta-(1-->6)-linked D-glucosamine backbone disaccharide with hydroxytetradecanoic acid in amide linkages. Unlike the structure described for the lipid A of the related human Helicobacter pylori gastric pathogen, which contains a C1 phosphate moiety, this lipid A presented phosphate groups at both the C1 and C4' positions, and contained no octadecanoyl fatty acid, which is present in H. pylori. The second lipid A structure had a different fatty acid composition in that 3-OH C(16) replaced most of the amide-linked 3-OH C(14).
    FEBS Letters 06/2001; 499(1-2):1-5. DOI:10.1016/S0014-5793(01)02496-6 · 3.34 Impact Factor
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    ABSTRACT: Structural studies of Bordetella endotoxins (LPSs) have revealed remarkable differences: (i) between their LPSs and those of other bacterial pathogens; (ii) among the LPSs of the seven identified Bordetella species; and (iii) among the LPSs of some Bordetella strains. The lipid As have the "classical" bisphosphorylated diglucosamine backbone but tend to have fewer and species-specific fatty acid components compared to those of other genera. Nevertheless, three strains of B. bronchiseptica have at least three different fatty acid distributions; however, the recently identified B. hinzii and B. trematum LPSs had identical lipid A structures. The B. pertussis core is a dodecasaccharide multi-branched structure bearing amino and carboxylic groups. Another unusual feature is the presence of free amino sugars in the central core region and a complex distal trisaccharide unit containing five amino groups of which four are acetylated and one is methylated. The B. pertussis LPS does not have O-chains and that of B. trematum had only a single O-unit, unlike the LPSs of all the other species of the smooth-type. The O-chain-free cores of non-B. pertussis LPSs were always built on the B. pertussis core model but most were species-specifically incomplete. The LPS structures of three B. bronchiseptica strains were found to be different from each other. The O-chains of B. bronchiseptica and B. parapertussis were almost identical and had some features in common with B. hinzii O-chain. Serological analyses are consistent with the determined LPS structures.
    Journal of Endotoxin Research 02/2001; 7(1):63-8. DOI:10.1177/09680519010070011101 · 3.06 Impact Factor
  • H. Rakotozafy · N. Louka · M. Thérisod · H. Thérisod · K. Allaf
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    ABSTRACT: Dehydration by Successive Pressure Drops (DDS) is a new unit operation, based on a repetition of compression/decompression cycles. In this work, we present the application of this drying process to baker's yeast. Drying rate, cycle efficiency, cell survival and the activities of four enzymes were evaluated. The effects of two parameters of DDS (PI and Dvp) on drying kinetics and product quality were studied, using the surface responses methodology. The results were also compared to those obtained with freeze-drying. PI had a positive effect on drying rate. Both PI and Dvp had an effect on cycle efficiency, particularly Dvp. Cell survival were much higher than that obtained with freeze-drying, with no significant impact of the parameters. The enzymatic activities were higher or close to the corresponding activities of freeze-dried sample, except the glucose-6-phosphate activity. The effects of PI and Dvp varied according to the enzyme.
    Drying Technology 11/2000; 18(10-10):2253-2271. DOI:10.1080/07373930008917841 · 1.77 Impact Factor
  • H. RAKOTOZAFY · N. LOUKA · M. THÉRISOD · H. THÉRISOD · K. ALLAF
    12th International Drying Symposium IDS2000, Netherlands; 08/2000
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    L Aussel · H Thérisod · D Karibian · M B Perry · M Bruneteau · M Caroff
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    ABSTRACT: The Silences of the Archives, the Reknown of the Story. The Martin Guerre affair has been told many times since Jean de Coras and Guillaume Lesueur published their stories in 1561. It is in many ways a perfect intrigue with uncanny resemblance, persuasive deception and a surprizing end when the two Martin stood face to face, memory to memory, before captivated judges and a guilty feeling Bertrande de Rols. The historian wanted to go beyond the known story in order to discover the world of the heroes. This research led to disappointments and surprizes as documents were discovered concerning the environment of Artigat’s inhabitants and bearing directly on the main characters thanks to notarial contracts. Along the way, study of the works of Coras and Lesueur took a new direction. Coming back to the affair a quarter century later did not result in finding new documents (some are perhaps still buried in Spanish archives), but by going back over her tracks, the historian could only be struck by the silences of the archives that refuse to reveal their secrets and, at the same time, by the possible openings they suggest, by the intuition that almost invisible threads link here and there characters and events.
    FEBS Letters 02/2000; 465(1):87-92. DOI:10.1016/S0014-5793(99)01722-6 · 3.34 Impact Factor
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    ABSTRACT: The Yersinia genus includes human and animal pathogens (plague, enterocolitis). The fine structures of the endotoxin lipids A of seven strains of Yersinia enterocolitica, Yersinia ruckeri and Yersinia pestis were determined and compared using mass spectrometry. These lipids differed in secondary acylation at C-2′: this was dodecanoic acid (C12) for two strains of Y. enterocolitica and Y. ruckeri, tetradecanoic acid (C14) in two other Y. enterocolitica and hexadecenoic acid (C16:1) in Y. pestis. The enterocolitica lipids having a mass identical to that of Escherichia coli were found to be structurally different. The results supported the idea of a relation between membrane fluidity and environmental adaptability in Yersinia.
    FEBS Letters 01/2000; 465(1):87-92. · 3.34 Impact Factor
  • H Therisod · Y Letourneux · M Therisod
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    ABSTRACT: N-phenyl-carbamate of D-mannonohydroxymolactone (I) was synthesized from mannose and was shown to be the best competitive inhibitor of beta-mannosidase so far reported (Ki = 25 nM).
    Bioorganic & Medicinal Chemistry Letters 03/1998; 8(4):371-2. DOI:10.1016/S0960-894X(98)00031-6 · 2.33 Impact Factor
  • M. Therisod · H. Therisod · A. Lubineau
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    ABSTRACT: A dinitrophényl ether III of gluconolactone oxime was synthesized and tested as an inhibitor of β-glucosidases. In contrast to the known compound II, III was found to be a modest inhibitor of β-glucosidase, but a good inhibitor of α-glucosidase.
    Bioorganic & Medicinal Chemistry Letters 09/1995; 5(18):2055-2058. DOI:10.1016/0960-894X(95)00366-2 · 2.33 Impact Factor

Publication Stats

181 Citations
30.91 Total Impact Points

Institutions

  • 2010
    • Université de La Rochelle
      • LIttoral ENvironnement et Sociétés (LIENSs)
      La Rochelle, Poitou-Charentes, France
  • 2000–2003
    • Université Paris-Sud 11
      • Institut de Biochimie et de Biophysique Moléculaire et Cellulaire (IBBMC)
      Orsay, Île-de-France, France
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France