TY - THES T1 - Isolation and identification of natural products and biosynthetic pathways from Photorhabdus and Xenorhabdus A1 - Brachmann,Alexander Oliver Y1 - 2010/01/06 N2 - The entomopathogenic bacteria of the genera Photorhabdus and Xenorhabdus display perfect model organisms to gain insights into the sophisticated interplay between symbiosis and pathogenicity. Moreover, numerous publications in the last years have demonstrated that these bacteria represent a rich source of secondary metabolites, which is exemplified in this work with the description of the novel xenofuranone compounds. The recently available genome sequence of Photorhabdus luminescens TT01 pointed out that many biosynthetic gene clusters remain silent as the corresponding product cannot be detected. The heterologous expression of a nonribosomal peptide synthetase, which resulted in the successful production of indigoidine, depicts one way to gain access on these cryptic gene clusters. In addition the genome sequence also enabled the identification of biosynthesis genes of the already known compound families of stilbenes and anthraquinones. Thereby a type II polyketide synthase cluster was identified, which is responsible for anthraquinone biosynthesis, representing only the second known type II PKS derived compound from a Gram-negative bacterium. Furthermore the identification of genes involved in stilbene biosynthesis led to the discovery of a unique and novel pathway, strongly differing from plant derived stilbenes. KW - Biosynthese KW - Xenorhabdus KW - Sekundärmetabolit KW - Stilbenderivate KW - Anthrachinonderivate CY - Saarbrücken PB - Universitäts- und Landesbibliothek AD - Postfach 151141, 66041 Saarbrücken UR - http://scidok.sulb.uni-saarland.de/volltexte/2010/2696 ER -