"FUNBIT has been involved in several multidisciplinary projects to study microbial interactions. Since 2016, FUNBIT has collaborated with four finished projects that have been published in high impact journals:
1. The group of Christine Beemelmans at HKI investigates fungus gardens in termites mounds to discover the chemical weapons used by Pseudoxylaria to fight against other fungi. Pseudoxylaria seemed to exudate more droplets (a process called ""guttation"") in close proximity to its competitor. The droplets contained several compounds, in high abundance, whose molecular mass had not been reported before. The localization of these compounds on the droplets was also visualized by MALDI - Imaging MS.
Guo, H., Kreuzenbeck, N. B., Otani, S., Garcia-Altares, M., Dahse, H. M., Weigel, C., ... & Beemelmanns, C. (2016). Pseudoxylallemycins A–F, Cyclic Tetrapeptides with Rare Allenyl Modifications Isolated from Pseudoxylaria sp. X802: A Competitor of Fungus-Growing Termite Cultivars. Organic Letters.
2. The stereaceous mushroom BY1 is able to produce polyenes yellow pigments to discourage insect larvae from feeding on it. The group of Prof. Dirk Hoffmeister at HKI unravelled the unusual biosynthesis of these compounds and discovered that a new enzyme (a polyketide synthase) catalyzes all steps, including the unprecedented shift of multiple double bonds, to assemble this anti-larval natural product. We now confirmed these findings by MALDI-mass spectrometry imaging and verified polyene accumulation on the wound. Only traces of the compounds were detected on the healthy area, where the mycelium shows only light yellow pigmentation.
Brandt, P., García‐Altares, M., Nett, M., Hertweck, C., & Hoffmeister, D. (2017). Induced Chemical Defense of a Mushroom by a Double‐Bond‐Shifting Polyene Synthase. Angewandte Chemie International Edition, 56(21), 5937-5941.
3. The group of Severin Sasso and Maria Mittag at Friedrich-Schiller-Universität Jena investigates interplay between microalgae, key contributors to carbon fixation on Earth, and other microorganisms in freshwater and marine ecosystems, using the green unicellular alga Chlamydomonas reinhardtii as a model organism. In a recent study, we showed that the bacterium Pseudomonas protegens strongly inhibits the growth and alters the morphology of Chlamydomonas reinhardtii. By Imaging MS and LC-MS analysis, we discovered that the natural products orfamides are produced by Pseudomonas protegens in the algal–bacterial interaction. Orfamide was discovered to alter cytosolic calcium homeostasis and inmobilization of the algae, which represent a novel biological activity for cyclic lipopeptides.
Aiyar, P., Schaeme, D., García-Altares, M., Flores, D.C. Dathe, H., Hertweck, C., Sasso, S. and Mittag, M., 2017. Antagonistic bacteria disrupt calcium homeostasis and immobilize algal cells. Nature communications, 8(1), p.1756.
4. The group of Pierre Stallforth at HKI focus on the interactions between the eukaryotic soil amoeba Dictyostelium discoideum and various soil bacteria to identify bacterial secondary metabolites that kill the amoebal predator. A recent study in which FUNBIT collaborated was accepted in Proc. Natl. Acad. Sci. describing a new cyclic lipopeptide produced by an inedible strain of Pseudomonas with amoebicidal activities.
Arp J, Götze S, Mukherji R, Mattern DJ, Garcia-Alatres M, Klapper M, Brock DA, Brakhage AA, Strassmann JE, Queller DC, Bardl B, Willing K, Peschel G, Stallforth P (2018) Synergistic activity of co-secreted natural products from amoebae-associated bacteria Proc. Natl. Acad. Sci. USA [Accepted]"
