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3 Publications visible to you, out of a total of 3

Abstract (Expand)

The psychotropic effects of Psilocybe "magic" mushrooms are caused by the l-tryptophan-derived alkaloid psilocybin. Despite their significance, the secondary metabolome of these fungi is poorly understood in general. Our analysis of four Psilocybe species identified harmane, harmine, and a range of other l-tryptophan-derived beta-carbolines as their natural products, which was confirmed by 1D and 2D NMR spectroscopy. Stable-isotope labeling with (13) C11 -l-tryptophan verified the beta-carbolines as biosynthetic products of these fungi. In addition, MALDI-MS imaging showed that beta-carbolines accumulate toward the hyphal apices. As potent inhibitors of monoamine oxidases, beta-carbolines are neuroactive compounds and interfere with psilocybin degradation. Therefore, our findings represent an unprecedented scenario of natural product pathways that diverge from the same building block and produce dissimilar compounds, yet contribute directly or indirectly to the same pharmacological effects.

Authors: F. Blei, S. Dorner, J. Fricke, F. Baldeweg, F. Trottmann, A. Komor, F. Meyer, C. Hertweck, D. Hoffmeister

Date Published: 13th Jan 2020

Publication Type: Journal

Abstract (Expand)

In both freshwater and marine ecosystems, phytoplankton are the most dominant primary producers, contributing substantially to aquatic food webs. Algicidal bacteria that can associate to microalgae from the phytoplankton have the capability to control the proliferation and even to lyse them. These bacteria thus play an important role in shaping species composition in pelagic environments. In this review, we discuss and categorise strategies used by algicidal bacteria for the attack on microalgae. We highlight the complex regulation of algicidal activity and defence responses that govern alga-bacteria interactions. We also discuss how algicidal bacteria impact algal physiology and metabolism and survey the existing algicidal metabolites and enzymes. The review illustrates that the ecological role of algicidal bacteria is not yet fully understood and critically discusses the challenges in obtaining ecologically relevant data.

Authors: N. Meyer, A. Bigalke, A. Kaulfuss, G. Pohnert

Date Published: 30th Sep 2017

Publication Type: Not specified

Abstract (Expand)

Algicidal bacteria can lyse microalgal blooms and trigger shifts within plankton communities. Resistant algal species can escape lysis, and have the opportunity to dominate the phytoplankton after a bacterial infection. Despite their important function in ecosystem regulation, little is known about mechanisms of resistance. Here, we show that the diatom Chaetoceros didymus releases eicosanoid oxylipins into the medium, and that the lytic algicidal bacterium, Kordia algicida, induces the production of several wound-activated oxylipins in this resistant diatom. Neither releases nor an induction occurs in the susceptible diatom Skeletonema costatum that is lysed by the bacterium within a few days. Among the upregulated oxylipins, hydroxylated eicosapentaenoic acids (HEPEs) dominate. However, also, resolvins, known lipid mediators in mammals, increase upon exposure of the algae to the algicidal bacteria. The prevailing hydroxylated fatty acid, 15-HEPE, significantly inhibits growth of K. algicida at a concentration of approximately 1 microM. The oxylipin production may represent an independent line of defense of the resistant alga, acting in addition to the previously reported upregulation of proteases.

Authors: N. Meyer, J. Rettner, M. Werner, O. Werz, G. Pohnert

Date Published: No date defined

Publication Type: Not specified

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