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11	Novel Fatty Acid Dioxygenases of Human and Plant Pathogenic Fungi : Studies by Gene Deletion and Expression Jernerén, Fredrik January 2011 (has links) The dioxygenase-cytochrome P450 fusion proteins (DOX-CYP) comprise a heme-containing enzyme family that shares structural and catalytic properties with mammalian prostaglandin H (PGH) synthases. 7,8-Linoleate diol synthase (7,8-LDS) of Gaeumannomyces graminis was first characterized, and DOX-CYP enzymes are of mechanistic and biological interest. The growing number of fungal genome sequences has revealed DOX-CYP homologues in medically and economically important species. The aim of this thesis was to identify novel members of the DOX-CYP fusion protein family. The devastating rice pathogen Magnaporthe oryzae contains two DOX-CYP genes. The fungus synthesizes 7S,8S-dihydroxyoctadecadienoic acid (7,8-DiHODE) by dioxygenation of linoleic acid to 8R-hydroperoxyoctadecadienoic acid (8R-HPODE), and subsequent isomerisation to the diol. 7,8-LDS of M. oryzae was identified by gene deletion, but the infection and reproduction processes of the Δ7,8-LDS strain were not altered. A mutant with constitutive protein kinase A activity profoundly changed the oxygenation profile, possibly due to post-translational modification. The human pathogens Aspergillus fumigatus and A. clavatus contain three DOX-CYP, designated psi producing oxygenase A (ppoA), ppoB, and ppoC, and form three oxylipins: 5S,8R-DiHODE, 8R,11S-DiHODE, and 10R-hydroxyoctadecadienoic acid. PpoA was identified as 5,8-LDS, and ppoC as 10R-DOX. The 8,11-linoleate hydroperoxide isomerase activity was reduced by two imidazole-containing P450 inhibitors, miconazole and 1-benzylimidazole. PpoB could not be linked to the biosynthesis of 8,11-DiHODE for the following reasons: First, the 8,11-hydroperoxide isomerase activity was retained in A. fumigatus ΔppoB strains. Second, the P450 domain of the deduced ppoB of A. clavatus lacks a heme-thiolate cysteine ligand, presumably essential for hydroperoxide isomerase activity. Linoleate 9R-DOX activities of Aspergillus terreus and Lasiodiplodia theobromae were discovered. 9R-HPODE was further converted into unstable allene oxides, as judged by the accumulation of their hydrolysis products, α- and γ-ketols. These allene oxide synthase activities were specific for 9R-hydroperoxides. The 9R-DOX and AOS were found to have unique characteristics. In conclusion, novel DOX-CYP enzymes were identified in human and plant pathogenic fungi. These enzymes might be involved in biological processes, and show interesting catalytic similarities to human PGH synthase and thromboxane synthase (CYP5A). aspergilli dioxygenase oxygenase Magnaporthe oryzae Gaeumannomyces graminis Lasiodiplodia theobromae jasmonic acid linoleate diol synthase cyclooxygenase prostaglandin H synthase cytochrome P450 oxylipin hydroperoxide isomerase allene oxide synthase Pharmaceutical pharmacology Farmaceutisk farmakologi
12	Biochemische Charakterisierung von PpoA aus Aspergillus nidulans / Biochemical Characterisation of PpoA from Aspergillus nidulans Brodhun, Florian 28 October 2009 (has links) No description available. 570 Biowissenschaften, Biologie Mathematics and Computer Science Aspergillus nidulans Fettsäure-Dioxygenase Oylipinbildung Psi-Faktor-produzierende Oxygenase (Ppo) Aspergillus nidulans fatty acid dioxygenase oxylipin formation psi-producing oxygenase (Ppo) Biologie SX
13	Synthèse asymétrique de l’épi-jasmonate de méthyle et de son énantiomère (ent-épi-jasmonate de méthyle) par voie chimique et enzymatique / Asymmetric synthesis of methyl epi-jasmonate and its enantiomer (methyl ent-epi-jasmonate) by chemo-stereoselective and enzymatic routes Deau, Emmanuel 08 April 2011 (has links) Les jasmonates de méthyle sont des oxylipines asymétriques impliquées dans les mécanismes de défense, de développement et de régulation des organismes photosynthétiques terrestres ou marins face à des stress biotiques et abiotiques. Parmi les quatre stéréoisomères, seuls l’épi-jasmonate et l’ent-épi-jasmonate de méthyle possèdent de bonnes propriétés organoleptiques mais aussi une forte activité phytohormonale permettant l’élicitation de métabolites secondaires bioactifs. En ciblant spécifiquement une hexokinase mitochondriale régulant le métabolisme des cellules cancéreuses, les jasmonates de méthyle constituent d’excellents candidats pour de nouveaux agents thérapeutiques. Dans la recherche constante de nouvelles molécules thérapeutiques issues du milieu naturel, notre laboratoire s’est donc focalisé sur la synthèse énantiosélective de l’épi-jasmonate et l’ent-épi-jasmonate de méthyle, au départ de diols bicycliques homochiraux monoprotégés dérivant du cyclooct-1,5-diène.Afin d’obtenir ces diols bicycliques énantiopurs, une stratégie innovante a consisté en l’étude de la réaction d’électrocyclisation du méso-époxyde dérivé du cyclooct-1,5-diène assistée par des ligands chiraux métallés diversement fonctionnalisés, les catalyseurs de Jacobsen. En mettant à profit notre savoir-faire sur les désymétrisations enzymatiques, une stratégie parallèle optant pour la résolution énantiosélective de diols homochiraux monocycliques, ou de diols bicycliques C2-symétriques nous a permis d’accéder à des silanyloxyindèn-5-ones chirales, précurseurs clé des cis-jasmonates de méthyle énantiopurs. Enfin, la synthèse racémique de deux jasmonoïdes clé, la (±)--jasmolactone, puis le (±)-épi-jasmonate de méthyle a été validée en 15 étapes à partir du cyclooct-1,5-diène. / Methyl jasmonates are asymmetric oxylipins involved in defensive, developmental and regulative mechanisms of terrestrial and marine photosynthetic organisms in response to biotic and abiotic challenges. Among the four stereoisomers, only methyl epi-jasmonate and ent-epi-jasmonate show good organoleptic properties but also phytohormonal activity allowing the elicitation of bioactive secondary metabolites. Because they specifically target a mitochondrial hexokinase regulating the metabolism of cancer cells, methyl jasmonates have become excellent candidates as new therapeutic agents. With a constant attention on new therapeutic agents derived from the natural environment, our laboratory has focused on the enantioselective synthesis of methyl epi-jasmonate and ent-epi-jasmonate using monoprotected homochiral diols derived from cyclooct-1,5-diene.In order to obtain these chiral bicyclic diols, an innovative strategy has involved the study of the chemo-stereoselective electrocyclization of the cyclooct-1,5-diene-derived meso-epoxide assisted by chiral metallated ligands known as Jacobsen’s catalysts. Taking advantage of our knowledge of enzymatic desymmetrization, a second strategy opting for the enantioselective resolution of monocyclic homochiral diols or C2-symmetric bicyclic diols led access to chiral silanyloxyinden-5-ones, key precursors to chiral methyl cis-jasmonates. Meanwhile, the racemic synthesis of (±)--jasmolactone and methyl (±)-epi-jasmonate was validated in 15 steps starting from cyclooct-1,5-diene. Épi-jasmonate de méthyle Ent-épi-jasmonate de méthyle Synthèse totale Oxylipine Phytohormone Catalyseurs de Jacobsen Désymétrisation enzymatique Diols énantiopurs Methyl epi-jasmonate Methyl ent-epi-jasmonate Total synthesis Oxylipin Phytohormone Jacobsen’s catalysts Enzymatic desymmetrization Chiral diols
14	Odour signals relevant to beetles in deadwood habitats - odorants, olfaction and behaviour. / Duftstoffsignale bedeutend für Käfer in Totholzhabitaten - Duftstoffe, Wahrnehmung und Verhalten. Holighaus, Gerrit 27 April 2012 (has links) No description available. 570 Biowissenschaften Biologie WYP 550 Forest Sciences and Forest Ecology Xylobios Ambrosiakäfer Holzzersetzung Wirt Volatile Wirtserkennung VOC Holz GC-EAD EAG Mykophagie Hefe LOX Oxylipine C8 Cerambycidae Lymexylidae Tenebrionidae Scolytinae Polyporales saproxylic fungus-growing wood decay host non-host volatiles host recognition VOC wood assessment GC-EAD EAG fungivory yeast secondary pheromone component LOX oxylipin eight-carbon 42.99 Biologie: Sonstiges 42.75 Insecta: Entomologie 35.70 Biochemie: Chemische Ökologie

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