57 research outputs found
Biotransformations using lipase enzymes in organic solvents
Enzymatic transformations in organic solvents have received increasing attention over the past 10 years and lipases have become by far the most popular enzymes in this area.The initial aim of the research was to assess the effect of small modifications to the acyl donor in the transesterification reactions mediated by the Candida cylindracea lipase. 2.2.2-Trichloroethyl butyrate (TCEB) was used as a standard for the rate studies. In the event the acyl donor, trichloroethyl methoxyacetate (TCEMA), accelerated the transesterification reaction with hexan-1-ol by an order of magnitude over that with TCEB. This observation, and the absence of an acceleration with trichloroethyl methoxypropionate (and ethyl 2- fluorobutyrate over ethyl butyrate) suggested that the effect is due to the ~oxygen. A solvent activity profile indicated that the most hydrophobic solvents supported faster initial rates. This was attributed to the ability of the hydrophilic solvents to strip the hydrated water from the enzyme surface thus deactivating it. The switch to organic solvents allowed a wider temperature range to be studied. For the reactions between heptan-2-ol and TCEMA the reaction could be conducted in the temperature range -23 C to 80 C. It was of interest to assess how the alcohol moiety effected the transesterification reaction. A series of alcohols were presented to the enzyme and a pattern emerged with substrates containing an acetylene functionality being processed faster than those with a vinyl group, which were faster than those containing a methyl group (all other groups being the same). A series of heterocyclic alcohols were presented to the enzyme and it was observed that the order of reaction was thiophene > furan > pyridyl. The secondary alcohols in this series, 2-thiopheneethan-1-ol and o pyridylethan-1-ol, were resolved at various temperatures from -1soc to sooc with no variation in. enantioselectivity. These are the first resolutions to be accomplished at temperatures below zero degrees
Ewiger Wald et la figure tutélaire de Richard Wagner
Ewiger Wald, Ă la croisĂ©e des genres spĂ©cifiquement germaniques, relĂšve Ă la fois du Kulturfilm, genre Ă prĂ©tention documentaire possĂ©dant une dimension Ă©ducative et morale, et du Heimatfilm, explorant le rapport entre lâhomme et la nature, et possĂ©dant des connotations raciales. Mais surtout, le film relĂšve dâune conception totalisatrice caractĂ©ristique de la tradition musicale allemande et incarnĂ©e par la figure tutĂ©laire de Wagner. Ewiger Wald adapte la forme sonore des opĂ©ras wagnĂ©riens au domaine visuel en construisant la forme cinĂ©matographique Ă partir de divers symboles signifiants, lâeau, le feu, le cycle de la renaissance succĂ©dant Ă la mort, dont lâinsistance renforce lâidĂ©ologie sous-jacente. La forĂȘt est reprĂ©sentĂ©e comme un modĂšle dont les hommes doivent adapter les lois Ă leur propre vie. Câest une maniĂšre de rendre lĂ©gitime lâidĂ©ologie raciale et belliciste en projetant sur la forĂȘt les principes du nazisme. Lâimportance accordĂ©e Ă la dĂ©gĂ©nĂ©rescence, ainsi quâĂ la lutte pour la survie, dans le mode dâexistence de la forĂȘt, permet de justifier le sacrifice pour la patrie ainsi que la thĂ©orie de lâespace vital. Ewiger Wald sâinspire Ă©galement de la pensĂ©e de Richard Wagner : la fusion de lâhomme et de la nature dans lâĆuvre dâart, lâunification des arts oĂč chacun abandonne son individualitĂ© pour se fondre dans un tout qui le dĂ©passe. Au-delĂ du film, lâidĂ©ologie nazie veut procĂ©der ainsi avec le peuple lui-mĂȘme, par la fusion des Ăąmes dans le FĂŒhrerprinzip. Lâappareil Ă©tatique est conçu comme un vaste spectacle qui prend en charge lâaffectivitĂ©. Les discours politiques, vides de contenus argumentatifs, excitent les reprĂ©sentations mentales du public par des termes symboliques, devenant eux-mĂȘmes musique. Lâentendement, inondĂ© de stimulations sensorielles, tend Ă abdiquer tout jugement.Ewiger Wald, zugleich Heimat- und Kulturfilm, bezieht sich auf Traditionen des deutschen Films, vor allem aber auf das auf Wagner zurĂŒckzufĂŒhrende Gesamtkunstwerk. Im Film wie in der Wagnerschen Oper wirken Musik, Bild und dichterisches Wort zusammen. Die filmische Umsetzung des Wagnerschen Ansatzes verwendet Symbole wie Wasser, Feuer, Tod und Wiedergeburt. Den Gesetzen des Waldes unterwerfen sich die Menschen, der Wald gerĂ€t somit zur ProjektionsflĂ€che der NS-Weltanschauung. Lebensraum und Lebenskampf stehen im Mittelpunkt sowie der Krieg gegen die Entartung, der den Tod fĂŒrs Vaterland rechtfertigt. Im Film bedingt die Musik Affekte, die den Zuschauer auf die NS-Ideologie einstimmen. Ewiger Wald bezieht sich auch auf das Denken Richard Wagners, auf das Einswerden von Mensch und Natur im Kunstwerk, auf das Einswerden aller KĂŒnste, auf das Aufgehen des Einzelnen im Ganzen, im FĂŒhrerprinzip. Politik gerĂ€t zum emotionsgeladenen Spektakel, politische Reden wollen nicht ĂŒberzeugen sondern das Publik vermittels einer symbolischen gleichsam musikalischen Sprache politisch aufreizen. Der Mensch wird seines Verstandes beraubt und auf seine stimulierten Sinne reduziert
Changes in Grape Maturity Induced by Spraying Ethanol
Three different ethanol solutions were sprayed onto Cabernet Sauvignon (Vitis vinifera L.) clusters during the ripening period: 2.5, 5 and 10% by volume in water. Controls were sprayed with water alone. Three different times of spraying were also tested: 8, 10 and 13 weeks post-flowering. One of the observed changes was a lower titratable acidity in grape samples at harvest, when the clusters were sprayed with ethanol at 10 weeks, in comparison with controls. The wines made with grapes treated with ethanol after mid-veraison, had higher ODs at 520 nm than did the controls. This may due to a combined effect of red pigment levels and acidity. In addition, following malolactic fermentation, the acidity levels of wines made with ethanoltreated grapes were slightly higher than those made with the control grapes. Spraying ethanol at 13 weeks post-flowering increased the berry weight by 10% at harvest without decreasing the °Brix value. The corresponding wines had similar degrees of alcohol. This observation was made for the first time in 2001
Uracil recognition by replicative DNA polymerases is limited to the archaea, not occurring with bacteria and eukarya
Family B DNA polymerases from archaea such as Pyrococcus furiosus, which live at temperatures âŒ100°C, specifically recognize uracil in DNA templates and stall replication in response to this base. Here it is demonstrated that interaction with uracil is not restricted to hyperthermophilic archaea and that the polymerase from mesophilic Methanosarcina acetivorans shows identical behaviour. The family B DNA polymerases replicate the genomes of archaea, one of the three fundamental domains of life. This publication further shows that the DNA replicating polymerases from the other two domains, bacteria (polymerase III) and eukaryotes (polymerases ÎŽ and Δ for nuclear DNA and polymerase Îł for mitochondrial) are also unable to recognize uracil. Uracil occurs in DNA as a result of deamination of cytosine, either in G:C base-pairs or, more rapidly, in single stranded regions produced, for example, during replication. The resulting G:U mis-pairs/single stranded uracils are promutagenic and, unless repaired, give rise to G:C to A:T transitions in 50% of the progeny. The confinement of uracil recognition to polymerases of the archaeal domain is discussed in terms of the DNA repair pathways necessary for the elimination of uracil
Malcolm X ; Daniel Guérin (introd.), L'autobiographie de Malcolm X, Paris, Grasset, 1966
Sanvoisin Jean. Malcolm X ; Daniel Guérin (introd.), L'autobiographie de Malcolm X, Paris, Grasset, 1966. In: L'Homme et la société, N. 2, 1966. pp. 187-188
Kenneth B. Clark, Ghetto noir, Paris, R. Laffont, 1966
Sanvoisin Jean. Kenneth B. Clark, Ghetto noir, Paris, R. Laffont, 1966. In: L'Homme et la société, N. 2, 1966. pp. 189-190
Marc Ferro, Victor Fay, Pierre BrouĂ© et alii, La rĂ©volution d'Octobre et le Mouvement ouvrier europĂ©en, Paris, Ătudes et documentation internationales, 1967
Sanvoisin Jean. Marc Ferro, Victor Fay, Pierre BrouĂ© et alii, La rĂ©volution d'Octobre et le Mouvement ouvrier europĂ©en, Paris, Ătudes et documentation internationales, 1967. In: L'Homme et la sociĂ©tĂ©, N. 6, 1967. pp. 190-192
Michel-Antoine Burnier, Les existentialistes et la politique, Paris, (Collection Idées), Gallimard, 1966
Sanvoisin Jean. Michel-Antoine Burnier, Les existentialistes et la politique, Paris, (Collection Idées), Gallimard, 1966. In: L'Homme et la société, N. 3, 1967. pp. 216-217
Michel-Antoine Burnier, Les existentialistes et la politique, Paris, (Collection Idées), Gallimard, 1966
Sanvoisin Jean. Michel-Antoine Burnier, Les existentialistes et la politique, Paris, (Collection Idées), Gallimard, 1966. In: L'Homme et la société, N. 3, 1967. pp. 216-217
RĂ©forme de lâentreprise ou contrĂŽle ouvrier ? DĂ©bat public entre MM. François Bloch-LainĂ©, Ernest Mandel et Gilbert Mathieu, Cahiers du C.E.S., n° 70-71, prĂ©facĂ© par J.-M. Vincent, E.D.I., Paris
Sanvoisin Jean. RĂ©forme de lâentreprise ou contrĂŽle ouvrier ? DĂ©bat public entre MM. François Bloch-LainĂ©, Ernest Mandel et Gilbert Mathieu, Cahiers du C.E.S., n° 70-71, prĂ©facĂ© par J.-M. Vincent, E.D.I., Paris. In: Autogestion : Ă©tudes, dĂ©bats, documents, N°4, 1967. pp. 171-173
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