Tuesday, August 12, 2008 - 2:00 PM
S78
Dead insects as a new source for secondary metabolites?
Helge B. Bode, Pharmaceutical Biotechnology, Saarland University, Building A4.1, Saarbrücken, 66123, Germany
Bacterial strains of the genus Xenorhabdus and Photorhabdus are well-known model-organisms to study nematode symbiosis and insect pathogenesis [1]. They live in symbiosis with nematodes of the genus Steinernema or Heterorhabditis, respectively, and after infection of insect larvae by these nematodes the bacteria are involved in killing the insect host using insecticidal proteins and other unknown factors. Although some secondary metabolites seem to play a crucial role in this symbiosis/pathogenesis life cycle of bacteria, nematode and insect host (and in the protection of the insect cadaver from free-living soil bacteria and fungi), almost nothing is known about the nature of the compounds involved, their biosynthesis and regulation and the physiology of these potent secondary metabolite producers. Therefore we have started to work on secondary metabolites from these interesting bacteria and could identify several new compounds including new anti-cancer pentapeptides by a combination of bioassay-based genome mining and sophisticated mass spectrometry and bioinformatics.
Moreover, we have elucidated the biosynthesis of the only non-plant stilbene known to date which is formed using an pathway different to the well-known plant biosynthesis [2], the biosynthesis of anthraquinones which are rarely found in Gram-negative bacteria [3], and the biosynthesis of the peptide/polyketide hybrid antibiotic xenocoumacin from Xenorhabdus nematophila in which a new formal biosynthesis of proline in involved.
[1] H. Goodrich-Blair, D. J. Clarke, Mol. Microbiol. 2007, 64 260.
[2] S. A. Joyce et al., Angew. Chem. Int. Ed. 2008, 47 1942.
[3] A. O. Brachmann et al., ChemBioChem 2007, 8 1721.
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See more of The Annual Meeting and Exhibition 2008 (August 10 - 14, 2008)