Many animals use low-molecular compounds for chemical defense. It has been postulated that a large number of these natural products are generated by symbiotic bacteria. However, due to the general inability to cultivate the suspected producers their study remains challenging. We follow a metagenomic approach to gain insights into the chemistry of uncultivated symbionts. From the total animal DNA containing all genomes metagenomic libraries are constructed, which are screened for biosynthesis genes of interest. These can then be used to identify the corresponding producer, to obtain insights into its biology and to create renewable sources of biomedically relevant compounds. Marine sponges are among the microbiologically most complex animals. In recent years our group has developed several strategies to overcome technical difficulties in identifying and isolating biosynthetic genes from the metagenomes of sponges. These methods allowed us to target gene clusters in Theonella swinhoei, Psammocinia aff. bulbosa and Mycale hentscheli and provided new insights into origin, evolution and biosynthesis of sponge-derived polyketides.
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J. Piel, D. Hui, G. Wen, D. Butzke, M. Platzer, N. Fusetani, S. Matsunaga, Proc. Natl. Acad. Sci. USA 101, 16222-16227 (2004).
T. Nguyen, K. Ishida, H. Jenke-Kodama, E. Dittmann, C. Gurgui, T. Hochmuth, S. Taudien, M. Platzer, C. Hertweck, J. Piel, Nature Biotechnol. 26, 225-233(2008).