Browsing Naturwissenschaften, Mathematik und Informatik by Referee "Zeeck, Axel Prof. Dr."
Now showing items 21-40 of 48
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Hoch cytotoxisches Kettapetin, Bhimamycine mit ungewöhnlichen Chromophoren und weitere neue Sekundärstoffe aus terrestrischen und marinen Bakterien
(2006-02-27)Nature is a source of medicinal agents since thousands of years, and an impressive number of modern drugs has been isolated from natural habitats, many based on their use firstly in traditional ... -
Pseudo-helicale und helicale Primärstrukturen aus spiroanellierten vier- und fünfgliedrigen Ringen: Synthesen und chiroptische Eigenschaften
(2006-01-24)The objective of this dissertation is a comparative study of the chiroptical properties of 1,2-spiroannulated helical hydrocarbons of three-, four- and five- membered rings. Towards this ... -
One-pot, Two-step Queuing Cascades Involving a Heck Coupling, π-Allylpalladium Trapping and Diels-Alder Reaction
(2006-01-23)In the first part of this study, palladium catalyzed reactions of mono-substituted bicyclopropylidenes (66B E) with iodobenzene (67) in the presence of dienophiles 68a b have been performed. ... -
Aufbau einer HPLC-UV-ESI-MS/MS-Datenbank und ihre Anwendung im Screening arktischer und antarktischer Meeresbakterien
(2005-10-21)Microorganisms from uncommon habitats are an attractive source for chemically and biologically outstanding natural compounds, for the interaction between different species in complex living ... -
Isolierung, Strukturaufklärung und Biosynthese von Sekundärmetaboliten endophytischer Pilze aus Algen und Pflanzen mariner Habitate
(2005-10-18)The core of the present thesis is the study of endophytic fungi with regard to their production of secondary metabolites. Altogether 56 fungal strains were both chemically and biologically ... -
Isolierung und Strukturaufklärung neuer Naturstoffe aus Bakterien und endophytischen Pilzen durch chemisches Screening
(2005-09-26)The present work deals with the isolation and structure elucidation of new secondary metabolites from bacteria and endophytic fungi, found by chemical screening. The antimicrobial and ... -
Untersuchungen zur Biosynthese und Aktivität ausgewählter Plecomakrolide sowie chemisches Screening von Actinomyceten
(2005-06-10)This Ph.D. thesis deals with the isolation and structure elucidation of microbial secondary metabolites and comprises studies of their biosynthesis and biological activity.The first part ... -
Dynamics of the B-A Transition of DNA Double Helices
(2005-05-20)Although the B-A transition of DNA is known for about 50 years, the dynamics of this transition has not been characterized yet. Experiments with stopped flow instrument showed that the ... -
Bioactive Secondary Metabolites from Marine and Terrestrial Bacteria: Isoquinolinequinones, Bacterial Compounds with a Novel Pharmacophor
(2005-01-17)After a chemical and biological pre-screening of bacterial extracts, 17 Streptomycetes (including eleven terrestrial and six marine-derived strains) and ten North Sea bacteria (including ... -
Towards a Total Synthesis of Mensacarcin
(2004-12-09)The work in this thesis has been concerned with attempts to develop concise synthetic routes to the natural product mensacarcin, which is a novel polyfunctionalised hexahydroanthracene ... -
Reaktionen des Bis(tert-butyl-methyl)ketazins mit Halogensilanen
(2004-10-22)This thesis refers to the synthesis of unknown acyclic und cyclic silylketazines. Reactions of monolithiated bis(tert-butyl-methyl)ketazine with chloro- and fluorosilanes lead to acyclic ... -
Darstellung bor- und phosphorhaltiger Ringe durch Reaktionen von Halogenboranen und -phosphanen mit Bis(tert.-butyl-methyl)ketazin
(2004-10-22)The first part of this thesis refers to the reactions of boroles, especially substitutions of remaining halogens and dehydrohalogenation reactions. The second part deals with similarities ... -
Synthetisch interessante Transformationen von Ring-anellierten (E,Z,E)-1,3,5-Hexatrienen
(2004-10-05)Twofold palladium-catalyzed coupling reactions (Heck reactions) of 1,2-dibromocycloalkenes with styrene or acrylates afforded 1,6-diphenyl- and 1,6-dialkoxycarbonyl-substituted ... -
Final Elucidation of the Absolute Configuration of Hormaomycin - Total Synthesis of Hormaomycin and Analogs
(2004-09-14)This work has been focused on the synthesis of hormaomycin and analogs, and prior to that, on the assignment of the absolute structure of unusual amino acids, which comprise hormaomycin, ... -
Charakterisierung eines neuen ATP-binding-cassette Transporters aus der ABCA-Subfamilie
(2004-09-08)This thesis describes the identification and characterisation of the novel ATP-binding-cassette gene ABCA5 and its putative rat orthologue rAbca5.ABCA5 was isolated and cloned from the human ... -
Identifizierung von Chitinasen mit fungizider Wirkung
(2004-02-11)Chitin is an linear unsoluble polymer consisting out of β-1,4-N-acetyl-D-glucosamin-units. This Polymer is the second most abundant polymer in nature and is a structural component of ... -
Reaktionen des Amino-di-<i>tert</i>-butylsilanols
(2003-11-26)In contrast to carbon chemistry in silicon chemistry a kinetic stabilization of compounds with two or three OH or NH2 groups bonded to one silicon atom is possible. The reaction of (Me3C)2Si(OH)Cl with liquid ammonia affords ... -
Molecular mechanisms of AMPA and kainate receptor gating and its implication in synaptic transmission
(2002-11-25)In this work we have studied the biophysical properties of AMPA and kainate receptors, which are found mainly in central synapses. AMPA receptors are thought to be tetrameric in nature. The ... -
Identifizierung und Charakterisierung von thermostabilen Uracil Glykosylasen von Archaeon Methanobacterium thermoautotrophicum und Bakterium Thermus thermophilus
(2002-05-22)Hydrolytic deamination reactions of cytosine and 5-methylcytosine results in highly mutagenic U/G and T/G mismatches, respectively. These processes are especially pronounced at high ... -
Identifizierung und Charakterisierung eines Vsr-Homologen aus Bacillus stearothermophilus
(2002-01-25)In this thesis, a method was developed which allows the identification of genes coding for proteins of a family where only one conserved region of homology is known. This method lead to the ...