Discussion

Marine fungi are an excellent source for new natural products. However, their potential to produce bioactive compounds is insufficiently investigated. One good example for this is the Scopulariopsis brevicaulis strain LF580 isolated from the marine sponge Tethya aurantium. The strain is known as the producer of the scopularide A and B. These cyclodepsipeptides show distinct cytotoxic activity against tumor cell lines [Yu et al., 2008]. For this reason the strain was selected for genome analysis and optimization processes for the cyclodepsipeptide production by random mutagenesis using UV radiation. For the screening of the mutant library for high producing scopularide A and B strains, we establish a novel fast and easy miniaturized screening approach. The method comprised a decreased cultivation volume, a fast extraction method and an optimized LC-MS analysis format [Kramer et al., 2014, in prep.]. One mutant strain demonstrated beside a changed morphological growth behavior also a faster growth combined with an enhanced production of the anti cancerous cyclodepsipeptides. In order to gain a deeper understanding of the hitherto uncharacterized molecular mechanisms underlying the production of scopularide A and B by Scopulariopsis brevicaulis, we applied quantitative proteomics to compare the proteomes extracted from the wild type strain and the mutant strain M26 harvested in the exponential growth phase. We have performed annotation and KEGG pathway analysis of proteins up-regulated and down-regulated proteins using BLAST2GO tool. We hypothesize that our iTRAQ-based quantitative proteomic approach will provide novel biological information useful for the optimization of scopularide production by Scopulariopsis brevicaulis.

Yu Z, Lang G, Kajahn I, Schmaljohann R, Imhoff JF (2008) Scopularides A and B, cyclodepsipeptides from an marine sponge-derived fungus, Scopulariopsis brevicaulis. J. Nat. Prod. 71: 1052-1054

Annemarie Kramer1), Hans Christian Beck2), Abhishek Kumar3)

1) Kiel Centre for Natural Products, GEOMAR Helmholtz Centre for Ocean Research Kiel, Am Kiel Kanal 44, 24116 Kiel, Germany
2) Centre for Clinical Proteomics, Department for Clinical Biochemistry and Pharmacology, Odense University Hospital, Sdr. Boulevard 29, 5000 Odense C, Denmark
3) Department of Genetics and Molecular Biology in Botany, Institute of Botany, Christians-Albrechts-University at Kiel, Olshausenstraße 40, 24098 Kiel, Germany