Occurrence Of Podosporin B In Podospora Decipiens And Sordaria Araneosa

From a fermentation of Sordaria araneosa aimed at producing the antifungal diterpenoid glycoside sordarin, we recently discovered a dehydro analogue of podosporin A [1] that we have named podosporin B. Both podosporin A and B were detected as inhibitors of the growth of Staphylococcus aureus in agar diffusion assays. Due to the low production of podosporin B by S. araneosa in the original fermentation in a medium containing glycerol, D-glucose, and tomato paste as carbon sources, we tested the culture in multiple media for several different fermentation times to see if podosporin B production could be increased. Alongside this, we surveyed members of the genus Podospora from the NPDI fungal culture collection to discover alternative sources for podosporin B. For S. araneosa, production of podosporin B could not be increased beyond that of the original fermentation medium. On the other hand, we have identified a culture of Podospora decipiens that produces podosporin B in potato dextrose broth at approximately a nine-fold higher titer relative to the original S. araneosa fermentation. These results demonstrate the potential for the discovery of alternative sources of biologically active compounds from the NPDI collection.

Fig. 1

Acknowledgements: We thank Gerald Bills, Texas Therapeutics Institute, the University of Texas Health Science Center, for helpful conversations.

References: [1] Weber, H. A., et al. (1988), J. Org. Chem., 53: 4567 – 4569.